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Type parameters

  • K

  • V

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Constructors

constructor

Properties

size: number

The number of entries in this OrderedMap.

Methods

  • Returns IterableIterator<[K, V]>

  • The yin to asMutable's yang. Because it applies to mutable collections, this operation is mutable and may return itself (though may not return itself, i.e. if the result is an empty collection). Once performed, the original mutable copy must no longer be mutated since it may be the immutable result.

    If possible, use withMutations to work with temporary mutable copies as it provides an easier to use API and considers many common optimizations.

    see

    Map#asMutable

    Returns <internal>.OrderedMap<K, V>

  • Another way to avoid creation of intermediate Immutable maps is to create a mutable copy of this collection. Mutable copies always return this, and thus shouldn't be used for equality. Your function should never return a mutable copy of a collection, only use it internally to create a new collection.

    If possible, use withMutations to work with temporary mutable copies as it provides an easier to use API and considers many common optimizations.

    Note: if the collection is already mutable, asMutable returns itself.

    Note: Not all methods can be used on a mutable collection or within withMutations! Read the documentation for each method to see if it is safe to use in withMutations.

    see

    Map#asImmutable

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type containing all entries except the last.

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Map containing no keys or values.

    const { Map } = require('immutable')
    Map({ key: 'value' }).clear()
    // Map {}

    Note: clear can be used in withMutations.

    Returns <internal>.OrderedMap<K, V>

  • Type parameters

    • KC

    • VC

    Parameters

    • Rest ...collections: Iterable<[KC, VC]>[]

    Returns <internal>.OrderedMap<K | KC, V | VC>

  • Type parameters

    • C

    Parameters

    • Rest ...collections: {}[]

    Returns <internal>.OrderedMap<string | K, V | C>

  • contains(value: V): boolean
  • Parameters

    • value: V

    Returns boolean

  • count(): number
  • count(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown): number
  • Returns the size of this Collection.

    Regardless of if this Collection can describe its size lazily (some Seqs cannot), this method will always return the correct size. E.g. it evaluates a lazy Seq if necessary.

    If predicate is provided, then this returns the count of entries in the Collection for which the predicate returns true.

    Returns number

  • Parameters

    Returns number

  • Returns a Seq.Keyed of counts, grouped by the return value of the grouper function.

    Note: This is not a lazy operation.

    Type parameters

    • G

    Parameters

    Returns <internal>.Map<G, number>

  • Returns a new Map which excludes this key.

    Note: delete cannot be safely used in IE8, but is provided to mirror the ES6 collection API.

    const { Map } = require('immutable')
    const originalMap = Map({
    key: 'value',
    otherKey: 'other value'
    })
    // Map { "key": "value", "otherKey": "other value" }
    originalMap.delete('otherKey')
    // Map { "key": "value" }

    Note: delete can be used in withMutations.

    alias

    remove

    Parameters

    • key: K

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Map which excludes the provided keys.

    const { Map } = require('immutable')
    const names = Map({ a: "Aaron", b: "Barry", c: "Connor" })
    names.deleteAll([ 'a', 'c' ])
    // Map { "b": "Barry" }

    Note: deleteAll can be used in withMutations.

    alias

    removeAll

    Parameters

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Map having removed the value at this keyPath. If any keys in keyPath do not exist, no change will occur.

    Note: deleteIn can be used in withMutations.

    alias

    removeIn

    Parameters

    Returns <internal>.OrderedMap<K, V>

  • An iterator of this Collection's entries as [ key, value ] tuples.

    Note: this will return an ES6 iterator which does not support Immutable.js sequence algorithms. Use entrySeq instead, if this is what you want.

    Returns IterableIterator<[K, V]>

  • Returns a new Seq.Indexed of [key, value] tuples.

    Returns <internal>.Indexed<[K, V]>

  • equals(other: unknown): boolean
  • True if this and the other Collection have value equality, as defined by Immutable.is().

    Note: This is equivalent to Immutable.is(this, other), but provided to allow for chained expressions.

    Parameters

    • other: unknown

    Returns boolean

  • every(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown): boolean
  • True if predicate returns true for all entries in the Collection.

    Parameters

    Returns boolean

  • Returns a new OrderedMap with only the entries for which the predicate function returns true.

    Note: filter() always returns a new instance, even if it results in not filtering out any values.

    Type parameters

    • F

    Parameters

    Returns <internal>.OrderedMap<K, F>

  • Parameters

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type with only the entries for which the predicate function returns false.

    const { Map } = require('immutable')
    Map({ a: 1, b: 2, c: 3, d: 4}).filterNot(x => x % 2 === 0)
    // Map { "a": 1, "c": 3 }

    Note: filterNot() always returns a new instance, even if it results in not filtering out any values.

    Parameters

    Returns <internal>.OrderedMap<K, V>

  • find(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown, notSetValue?: V): undefined | V
  • Returns the first value for which the predicate returns true.

    Parameters

    Returns undefined | V

  • findEntry(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown, notSetValue?: V): undefined | [K, V]
  • Returns the first [key, value] entry for which the predicate returns true.

    Parameters

    Returns undefined | [K, V]

  • findKey(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown): undefined | K
  • Returns the key for which the predicate returns true.

    Parameters

    Returns undefined | K

  • findLast(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown, notSetValue?: V): undefined | V
  • Returns the last value for which the predicate returns true.

    Note: predicate will be called for each entry in reverse.

    Parameters

    Returns undefined | V

  • findLastEntry(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown, notSetValue?: V): undefined | [K, V]
  • Returns the last [key, value] entry for which the predicate returns true.

    Note: predicate will be called for each entry in reverse.

    Parameters

    Returns undefined | [K, V]

  • findLastKey(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown): undefined | K
  • Returns the last key for which the predicate returns true.

    Note: predicate will be called for each entry in reverse.

    Parameters

    Returns undefined | K

  • first<NSV>(notSetValue?: NSV): V | NSV
  • In case the Collection is not empty returns the first element of the Collection. In case the Collection is empty returns the optional default value if provided, if no default value is provided returns undefined.

    Type parameters

    • NSV = undefined

    Parameters

    • Optional notSetValue: NSV

    Returns V | NSV

  • Flattens nested Collections.

    Will deeply flatten the Collection by default, returning a Collection of the same type, but a depth can be provided in the form of a number or boolean (where true means to shallowly flatten one level). A depth of 0 (or shallow: false) will deeply flatten.

    Flattens only others Collection, not Arrays or Objects.

    Note: flatten(true) operates on Collection<unknown, Collection<K, V>> and returns Collection<K, V>

    Parameters

    • Optional depth: number

    Returns <internal>.Collection<unknown, unknown>

  • Parameters

    • Optional shallow: boolean

    Returns <internal>.Collection<unknown, unknown>

  • see

    Collection.Keyed.flip

    Returns <internal>.OrderedMap<V, K>

  • forEach(sideEffect: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => unknown, context?: unknown): number
  • The sideEffect is executed for every entry in the Collection.

    Unlike Array#forEach, if any call of sideEffect returns false, the iteration will stop. Returns the number of entries iterated (including the last iteration which returned false).

    Parameters

    Returns number

  • get<NSV>(key: K, notSetValue: NSV): V | NSV
  • get(key: K): undefined | V
  • Returns the value associated with the provided key, or notSetValue if the Collection does not contain this key.

    Note: it is possible a key may be associated with an undefined value, so if notSetValue is not provided and this method returns undefined, that does not guarantee the key was not found.

    Type parameters

    • NSV

    Parameters

    • key: K
    • notSetValue: NSV

    Returns V | NSV

  • Parameters

    • key: K

    Returns undefined | V

  • getIn(searchKeyPath: Iterable<unknown>, notSetValue?: unknown): unknown
  • Returns the value found by following a path of keys or indices through nested Collections.

    const { Map, List } = require('immutable')
    const deepData = Map({ x: List([ Map({ y: 123 }) ]) });
    deepData.getIn(['x', 0, 'y']) // 123

    Plain JavaScript Object or Arrays may be nested within an Immutable.js Collection, and getIn() can access those values as well:

    const { Map, List } = require('immutable')
    const deepData = Map({ x: [ { y: 123 } ] });
    deepData.getIn(['x', 0, 'y']) // 123

    Parameters

    • searchKeyPath: Iterable<unknown>
    • Optional notSetValue: unknown

    Returns unknown

  • Returns a Collection.Keyed of Collection.Keyeds, grouped by the return value of the grouper function.

    Note: This is always an eager operation.

    const { List, Map } = require('immutable')
    const listOfMaps = List([
    Map({ v: 0 }),
    Map({ v: 1 }),
    Map({ v: 1 }),
    Map({ v: 0 }),
    Map({ v: 2 })
    ])
    const groupsOfMaps = listOfMaps.groupBy(x => x.get('v'))
    // Map {
    // 0: List [ Map{ "v": 0 }, Map { "v": 0 } ],
    // 1: List [ Map{ "v": 1 }, Map { "v": 1 } ],
    // 2: List [ Map{ "v": 2 } ],
    // }

    Type parameters

    • G

    Parameters

    Returns <internal>.Keyed<G, <internal>.Collection<K, V>>

  • has(key: K): boolean
  • True if a key exists within this Collection, using Immutable.is to determine equality

    Parameters

    • key: K

    Returns boolean

  • hasIn(searchKeyPath: Iterable<unknown>): boolean
  • True if the result of following a path of keys or indices through nested Collections results in a set value.

    Parameters

    Returns boolean

  • hashCode(): number
  • Computes and returns the hashed identity for this Collection.

    The hashCode of a Collection is used to determine potential equality, and is used when adding this to a Set or as a key in a Map, enabling lookup via a different instance.

    const a = List([ 1, 2, 3 ]);
    const b = List([ 1, 2, 3 ]);
    assert.notStrictEqual(a, b); // different instances
    const set = Set([ a ]);
    assert.equal(set.has(b), true);

    If two values have the same hashCode, they are not guaranteed to be equal. If two values have different hashCodes, they must not be equal.

    Returns number

  • includes(value: V): boolean
  • True if a value exists within this Collection, using Immutable.is to determine equality

    alias

    contains

    Parameters

    • value: V

    Returns boolean

  • isEmpty(): boolean
  • Returns true if this Collection includes no values.

    For some lazy Seq, isEmpty might need to iterate to determine emptiness. At most one iteration will occur.

    Returns boolean

  • True if iter includes every value in this Collection.

    Parameters

    Returns boolean

  • True if this Collection includes every value in iter.

    Parameters

    Returns boolean

  • join(separator?: string): string
  • Joins values together as a string, inserting a separator between each. The default separator is ",".

    Parameters

    • Optional separator: string

    Returns string

  • keyOf(searchValue: V): undefined | K
  • Returns the key associated with the search value, or undefined.

    Parameters

    • searchValue: V

    Returns undefined | K

  • Returns a new Seq.Indexed of the keys of this Collection, discarding values.

    Returns <internal>.Indexed<K>

  • An iterator of this Collection's keys.

    Note: this will return an ES6 iterator which does not support Immutable.js sequence algorithms. Use keySeq instead, if this is what you want.

    Returns IterableIterator<K>

  • last<NSV>(notSetValue?: NSV): V | NSV
  • In case the Collection is not empty returns the last element of the Collection. In case the Collection is empty returns the optional default value if provided, if no default value is provided returns undefined.

    Type parameters

    • NSV = undefined

    Parameters

    • Optional notSetValue: NSV

    Returns V | NSV

  • lastKeyOf(searchValue: V): undefined | K
  • Returns the last key associated with the search value, or undefined.

    Parameters

    • searchValue: V

    Returns undefined | K

  • Returns a new OrderedMap with values passed through a mapper function.

    OrderedMap({ a: 1, b: 2 }).map(x => 10 * x)
    // OrderedMap { "a": 10, "b": 20 }

    Note: map() always returns a new instance, even if it produced the same value at every step.

    Type parameters

    • M

    Parameters

    Returns <internal>.OrderedMap<K, M>

  • see

    Collection.Keyed.mapEntries

    Type parameters

    • KM

    • VM

    Parameters

    • mapper: (entry: [K, V], index: number, iter: <internal>.OrderedMap<K, V>) => undefined | [KM, VM]
    • Optional context: unknown

    Returns <internal>.OrderedMap<KM, VM>

  • max(comparator?: (valueA: V, valueB: V) => number): undefined | V
  • Returns the maximum value in this collection. If any values are comparatively equivalent, the first one found will be returned.

    The comparator is used in the same way as Collection#sort. If it is not provided, the default comparator is >.

    When two values are considered equivalent, the first encountered will be returned. Otherwise, max will operate independent of the order of input as long as the comparator is commutative. The default comparator > is commutative only when types do not differ.

    If comparator returns 0 and either value is NaN, undefined, or null, that value will be returned.

    Parameters

    • Optional comparator: (valueA: V, valueB: V) => number
        • (valueA: V, valueB: V): number
        • Parameters

          • valueA: V
          • valueB: V

          Returns number

    Returns undefined | V

  • maxBy<C>(comparatorValueMapper: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => C, comparator?: (valueA: C, valueB: C) => number): undefined | V
  • Like max, but also accepts a comparatorValueMapper which allows for comparing by more sophisticated means:

    const { List, } = require('immutable');
    const l = List([
    { name: 'Bob', avgHit: 1 },
    { name: 'Max', avgHit: 3 },
    { name: 'Lili', avgHit: 2 } ,
    ]);
    l.maxBy(i => i.avgHit); // will output { name: 'Max', avgHit: 3 }

    Type parameters

    • C

    Parameters

    • comparatorValueMapper: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => C
    • Optional comparator: (valueA: C, valueB: C) => number
        • (valueA: C, valueB: C): number
        • Parameters

          • valueA: C
          • valueB: C

          Returns number

    Returns undefined | V

  • Returns a new OrderedMap resulting from merging the provided Collections (or JS objects) into this OrderedMap. In other words, this takes each entry of each collection and sets it on this OrderedMap.

    Note: Values provided to merge are shallowly converted before being merged. No nested values are altered.

    const { OrderedMap } = require('immutable')
    const one = OrderedMap({ a: 10, b: 20, c: 30 })
    const two = OrderedMap({ b: 40, a: 50, d: 60 })
    one.merge(two) // OrderedMap { "a": 50, "b": 40, "c": 30, "d": 60 }
    two.merge(one) // OrderedMap { "b": 20, "a": 10, "d": 60, "c": 30 }

    Note: merge can be used in withMutations.

    alias

    concat

    Type parameters

    • KC

    • VC

    Parameters

    • Rest ...collections: Iterable<[KC, VC]>[]

    Returns <internal>.OrderedMap<K | KC, V | VC>

  • Type parameters

    • C

    Parameters

    • Rest ...collections: {}[]

    Returns <internal>.OrderedMap<string | K, V | C>

  • Like merge(), but when two compatible collections are encountered with the same key, it merges them as well, recursing deeply through the nested data. Two collections are considered to be compatible (and thus will be merged together) if they both fall into one of three categories: keyed (e.g., Maps, Records, and objects), indexed (e.g., Lists and arrays), or set-like (e.g., Sets). If they fall into separate categories, mergeDeep will replace the existing collection with the collection being merged in. This behavior can be customized by using mergeDeepWith().

    Note: Indexed and set-like collections are merged using concat()/union() and therefore do not recurse.

    const { Map } = require('immutable')
    const one = Map({ a: Map({ x: 10, y: 10 }), b: Map({ x: 20, y: 50 }) })
    const two = Map({ a: Map({ x: 2 }), b: Map({ y: 5 }), c: Map({ z: 3 }) })
    one.mergeDeep(two)
    // Map {
    // "a": Map { "x": 2, "y": 10 },
    // "b": Map { "x": 20, "y": 5 },
    // "c": Map { "z": 3 }
    // }

    Note: mergeDeep can be used in withMutations.

    Parameters

    • Rest ...collections: (Iterable<[K, V]> | {})[]

    Returns <internal>.OrderedMap<K, V>

  • A combination of updateIn and mergeDeep, returning a new Map, but performing the deep merge at a point arrived at by following the keyPath. In other words, these two lines are equivalent:

    map.updateIn(['a', 'b', 'c'], abc => abc.mergeDeep(y))
    map.mergeDeepIn(['a', 'b', 'c'], y)

    Note: mergeDeepIn can be used in withMutations.

    Parameters

    • keyPath: Iterable<unknown>
    • Rest ...collections: unknown[]

    Returns <internal>.OrderedMap<K, V>

  • mergeDeepWith(merger: (oldVal: unknown, newVal: unknown, key: unknown) => unknown, ...collections: (Iterable<[K, V]> | {})[]): <internal>.OrderedMap<K, V>
  • Like mergeDeep(), but when two non-collections or incompatible collections are encountered at the same key, it uses the merger function to determine the resulting value. Collections are considered incompatible if they fall into separate categories between keyed, indexed, and set-like.

    const { Map } = require('immutable')
    const one = Map({ a: Map({ x: 10, y: 10 }), b: Map({ x: 20, y: 50 }) })
    const two = Map({ a: Map({ x: 2 }), b: Map({ y: 5 }), c: Map({ z: 3 }) })
    one.mergeDeepWith((oldVal, newVal) => oldVal / newVal, two)
    // Map {
    // "a": Map { "x": 5, "y": 10 },
    // "b": Map { "x": 20, "y": 10 },
    // "c": Map { "z": 3 }
    // }

    Note: mergeDeepWith can be used in withMutations.

    Parameters

    • merger: (oldVal: unknown, newVal: unknown, key: unknown) => unknown
        • (oldVal: unknown, newVal: unknown, key: unknown): unknown
        • Parameters

          • oldVal: unknown
          • newVal: unknown
          • key: unknown

          Returns unknown

    • Rest ...collections: (Iterable<[K, V]> | {})[]

    Returns <internal>.OrderedMap<K, V>

  • A combination of updateIn and merge, returning a new Map, but performing the merge at a point arrived at by following the keyPath. In other words, these two lines are equivalent:

    map.updateIn(['a', 'b', 'c'], abc => abc.merge(y))
    map.mergeIn(['a', 'b', 'c'], y)

    Note: mergeIn can be used in withMutations.

    Parameters

    • keyPath: Iterable<unknown>
    • Rest ...collections: unknown[]

    Returns <internal>.OrderedMap<K, V>

  • Like merge(), mergeWith() returns a new Map resulting from merging the provided Collections (or JS objects) into this Map, but uses the merger function for dealing with conflicts.

    const { Map } = require('immutable')
    const one = Map({ a: 10, b: 20, c: 30 })
    const two = Map({ b: 40, a: 50, d: 60 })
    one.mergeWith((oldVal, newVal) => oldVal / newVal, two)
    // { "a": 0.2, "b": 0.5, "c": 30, "d": 60 }
    two.mergeWith((oldVal, newVal) => oldVal / newVal, one)
    // { "b": 2, "a": 5, "d": 60, "c": 30 }

    Note: mergeWith can be used in withMutations.

    Parameters

    • merger: (oldVal: V, newVal: V, key: K) => V
        • (oldVal: V, newVal: V, key: K): V
        • Parameters

          • oldVal: V
          • newVal: V
          • key: K

          Returns V

    • Rest ...collections: (Iterable<[K, V]> | {})[]

    Returns <internal>.OrderedMap<K, V>

  • min(comparator?: (valueA: V, valueB: V) => number): undefined | V
  • Returns the minimum value in this collection. If any values are comparatively equivalent, the first one found will be returned.

    The comparator is used in the same way as Collection#sort. If it is not provided, the default comparator is <.

    When two values are considered equivalent, the first encountered will be returned. Otherwise, min will operate independent of the order of input as long as the comparator is commutative. The default comparator < is commutative only when types do not differ.

    If comparator returns 0 and either value is NaN, undefined, or null, that value will be returned.

    Parameters

    • Optional comparator: (valueA: V, valueB: V) => number
        • (valueA: V, valueB: V): number
        • Parameters

          • valueA: V
          • valueB: V

          Returns number

    Returns undefined | V

  • minBy<C>(comparatorValueMapper: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => C, comparator?: (valueA: C, valueB: C) => number): undefined | V
  • Like min, but also accepts a comparatorValueMapper which allows for comparing by more sophisticated means:

    const { List, } = require('immutable');
    const l = List([
    { name: 'Bob', avgHit: 1 },
    { name: 'Max', avgHit: 3 },
    { name: 'Lili', avgHit: 2 } ,
    ]);
    l.minBy(i => i.avgHit); // will output { name: 'Bob', avgHit: 1 }

    Type parameters

    • C

    Parameters

    • comparatorValueMapper: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => C
    • Optional comparator: (valueA: C, valueB: C) => number
        • (valueA: C, valueB: C): number
        • Parameters

          • valueA: C
          • valueB: C

          Returns number

    Returns undefined | V

  • reduce<R>(reducer: (reduction: R, value: V, key: K, iter: <internal>.OrderedMap<K, V>) => R, initialReduction: R, context?: unknown): R
  • reduce<R>(reducer: (reduction: V | R, value: V, key: K, iter: <internal>.OrderedMap<K, V>) => R): R
  • Reduces the Collection to a value by calling the reducer for every entry in the Collection and passing along the reduced value.

    If initialReduction is not provided, the first item in the Collection will be used.

    see

    Array#reduce.

    Type parameters

    • R

    Parameters

    Returns R

  • Type parameters

    • R

    Parameters

    Returns R

  • reduceRight<R>(reducer: (reduction: R, value: V, key: K, iter: <internal>.OrderedMap<K, V>) => R, initialReduction: R, context?: unknown): R
  • reduceRight<R>(reducer: (reduction: V | R, value: V, key: K, iter: <internal>.OrderedMap<K, V>) => R): R
  • Reduces the Collection in reverse (from the right side).

    Note: Similar to this.reverse().reduce(), and provided for parity with Array#reduceRight.

    Type parameters

    • R

    Parameters

    Returns R

  • Type parameters

    • R

    Parameters

    Returns R

  • Parameters

    • key: K

    Returns <internal>.OrderedMap<K, V>

  • Parameters

    Returns <internal>.OrderedMap<K, V>

  • Parameters

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type containing all entries except the first.

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type in reverse order.

    Returns <internal>.OrderedMap<K, V>

  • Returns a new OrderedMap also containing the new key, value pair. If an equivalent key already exists in this OrderedMap, it will be replaced while maintaining the existing order.

    const { OrderedMap } = require('immutable')
    const originalMap = OrderedMap({a:1, b:1, c:1})
    const updatedMap = originalMap.set('b', 2)

    originalMap
    // OrderedMap {a: 1, b: 1, c: 1}
    updatedMap
    // OrderedMap {a: 1, b: 2, c: 1}

    Note: set can be used in withMutations.

    Parameters

    • key: K
    • value: V

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Map having set value at this keyPath. If any keys in keyPath do not exist, a new immutable Map will be created at that key.

    const { Map } = require('immutable')
    const originalMap = Map({
    subObject: Map({
    subKey: 'subvalue',
    subSubObject: Map({
    subSubKey: 'subSubValue'
    })
    })
    })

    const newMap = originalMap.setIn(['subObject', 'subKey'], 'ha ha!')
    // Map {
    // "subObject": Map {
    // "subKey": "ha ha!",
    // "subSubObject": Map { "subSubKey": "subSubValue" }
    // }
    // }

    const newerMap = originalMap.setIn(
    ['subObject', 'subSubObject', 'subSubKey'],
    'ha ha ha!'
    )
    // Map {
    // "subObject": Map {
    // "subKey": "subvalue",
    // "subSubObject": Map { "subSubKey": "ha ha ha!" }
    // }
    // }

    Plain JavaScript Object or Arrays may be nested within an Immutable.js Collection, and setIn() can update those values as well, treating them immutably by creating new copies of those values with the changes applied.

    const { Map } = require('immutable')
    const originalMap = Map({
    subObject: {
    subKey: 'subvalue',
    subSubObject: {
    subSubKey: 'subSubValue'
    }
    }
    })

    originalMap.setIn(['subObject', 'subKey'], 'ha ha!')
    // Map {
    // "subObject": {
    // subKey: "ha ha!",
    // subSubObject: { subSubKey: "subSubValue" }
    // }
    // }

    If any key in the path exists but cannot be updated (such as a primitive like number or a custom Object like Date), an error will be thrown.

    Note: setIn can be used in withMutations.

    Parameters

    • keyPath: Iterable<unknown>
    • value: unknown

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type which excludes the first amount entries from this Collection.

    Parameters

    • amount: number

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type which excludes the last amount entries from this Collection.

    Parameters

    • amount: number

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type which includes entries starting from when predicate first returns true.

    const { List } = require('immutable')
    List([ 'dog', 'frog', 'cat', 'hat', 'god' ])
    .skipUntil(x => x.match(/hat/))
    // List [ "hat", "god" ]

    Parameters

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type which includes entries starting from when predicate first returns false.

    const { List } = require('immutable')
    List([ 'dog', 'frog', 'cat', 'hat', 'god' ])
    .skipWhile(x => x.match(/g/))
    // List [ "cat", "hat", "god" ]

    Parameters

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type representing a portion of this Collection from start up to but not including end.

    If begin is negative, it is offset from the end of the Collection. e.g. slice(-2) returns a Collection of the last two entries. If it is not provided the new Collection will begin at the beginning of this Collection.

    If end is negative, it is offset from the end of the Collection. e.g. slice(0, -1) returns a Collection of everything but the last entry. If it is not provided, the new Collection will continue through the end of this Collection.

    If the requested slice is equivalent to the current Collection, then it will return itself.

    Parameters

    • Optional begin: number
    • Optional end: number

    Returns <internal>.OrderedMap<K, V>

  • some(predicate: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => boolean, context?: unknown): boolean
  • True if predicate returns true for any entry in the Collection.

    Parameters

    Returns boolean

  • Returns a new Collection of the same type which includes the same entries, stably sorted by using a comparator.

    If a comparator is not provided, a default comparator uses < and >.

    comparator(valueA, valueB):

    • Returns 0 if the elements should not be swapped.
    • Returns -1 (or any negative number) if valueA comes before valueB
    • Returns 1 (or any positive number) if valueA comes after valueB
    • Is pure, i.e. it must always return the same value for the same pair of values.

    When sorting collections which have no defined order, their ordered equivalents will be returned. e.g. map.sort() returns OrderedMap.

    const { Map } = require('immutable')
    Map({ "c": 3, "a": 1, "b": 2 }).sort((a, b) => {
    if (a < b) { return -1; }
    if (a > b) { return 1; }
    if (a === b) { return 0; }
    });
    // OrderedMap { "a": 1, "b": 2, "c": 3 }

    Note: sort() Always returns a new instance, even if the original was already sorted.

    Note: This is always an eager operation.

    Parameters

    • Optional comparator: (valueA: V, valueB: V) => number
        • (valueA: V, valueB: V): number
        • Parameters

          • valueA: V
          • valueB: V

          Returns number

    Returns <internal>.OrderedMap<K, V>

  • Like sort, but also accepts a comparatorValueMapper which allows for sorting by more sophisticated means:

    const { Map } = require('immutable')
    const beattles = Map({
    John: { name: "Lennon" },
    Paul: { name: "McCartney" },
    George: { name: "Harrison" },
    Ringo: { name: "Starr" },
    });
    beattles.sortBy(member => member.name);

    Note: sortBy() Always returns a new instance, even if the original was already sorted.

    Note: This is always an eager operation.

    Type parameters

    • C

    Parameters

    • comparatorValueMapper: (value: V, key: K, iter: <internal>.OrderedMap<K, V>) => C
    • Optional comparator: (valueA: C, valueB: C) => number
        • (valueA: C, valueB: C): number
        • Parameters

          • valueA: C
          • valueB: C

          Returns number

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type which includes the first amount entries from this Collection.

    Parameters

    • amount: number

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type which includes the last amount entries from this Collection.

    Parameters

    • amount: number

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type which includes entries from this Collection as long as the predicate returns false.

    const { List } = require('immutable')
    List([ 'dog', 'frog', 'cat', 'hat', 'god' ])
    .takeUntil(x => x.match(/at/))
    // List [ "dog", "frog" ]

    Parameters

    Returns <internal>.OrderedMap<K, V>

  • Returns a new Collection of the same type which includes entries from this Collection as long as the predicate returns true.

    const { List } = require('immutable')
    List([ 'dog', 'frog', 'cat', 'hat', 'god' ])
    .takeWhile(x => x.match(/o/))
    // List [ "dog", "frog" ]

    Parameters

    Returns <internal>.OrderedMap<K, V>

  • toArray(): [K, V][]
  • Shallowly converts this collection to an Array.

    Returns [K, V][]

  • Returns an Seq.Indexed of the values of this Collection, discarding keys.

    Returns <internal>.Indexed<V>

  • toJS(): {}
  • Deeply converts this Keyed collection to equivalent native JavaScript Object.

    Converts keys to Strings.

    Returns {}

    • [key: string]: unknown
  • toJSON(): {}
  • Shallowly converts this Keyed collection to equivalent native JavaScript Object.

    Converts keys to Strings.

    Returns {}

    • [key: string]: V
  • Returns a Seq.Keyed from this Collection where indices are treated as keys.

    This is useful if you want to operate on an Collection.Indexed and preserve the [index, value] pairs.

    The returned Seq will have identical iteration order as this Collection.

    const { Seq } = require('immutable')
    const indexedSeq = Seq([ 'A', 'B', 'C' ])
    // Seq [ "A", "B", "C" ]
    indexedSeq.filter(v => v === 'B')
    // Seq [ "B" ]
    const keyedSeq = indexedSeq.toKeyedSeq()
    // Seq { 0: "A", 1: "B", 2: "C" }
    keyedSeq.filter(v => v === 'B')
    // Seq { 1: "B" }

    Returns <internal>.Keyed<K, V>

  • Converts this Collection to a List, discarding keys.

    This is similar to List(collection), but provided to allow for chained expressions. However, when called on Map or other keyed collections, collection.toList() discards the keys and creates a list of only the values, whereas List(collection) creates a list of entry tuples.

    const { Map, List } = require('immutable')
    var myMap = Map({ a: 'Apple', b: 'Banana' })
    List(myMap) // List [ [ "a", "Apple" ], [ "b", "Banana" ] ]
    myMap.toList() // List [ "Apple", "Banana" ]

    Returns <internal>.List<V>

  • Converts this Collection to a Map, Throws if keys are not hashable.

    Note: This is equivalent to Map(this.toKeyedSeq()), but provided for convenience and to allow for chained expressions.

    Returns <internal>.Map<K, V>

  • toObject(): {}
  • Shallowly converts this Collection to an Object.

    Converts keys to Strings.

    Returns {}

    • [key: string]: V
  • Converts this Collection to a Map, maintaining the order of iteration.

    Note: This is equivalent to OrderedMap(this.toKeyedSeq()), but provided for convenience and to allow for chained expressions.

    Returns <internal>.OrderedMap<K, V>

  • Converts this Collection to a Set, maintaining the order of iteration and discarding keys.

    Note: This is equivalent to OrderedSet(this.valueSeq()), but provided for convenience and to allow for chained expressions.

    Returns <internal>.OrderedSet<V>

  • Returns Seq.Keyed.

    override

    Returns <internal>.Keyed<K, V>

  • Converts this Collection to a Set, discarding keys. Throws if values are not hashable.

    Note: This is equivalent to Set(this), but provided to allow for chained expressions.

    Returns <internal>.Set<V>

  • Returns a Seq.Set of the values of this Collection, discarding keys.

    Returns <internal>.Set<V>

  • Converts this Collection to a Stack, discarding keys. Throws if values are not hashable.

    Note: This is equivalent to Stack(this), but provided to allow for chained expressions.

    Returns <internal>.Stack<V>

  • Returns a new Map having updated the value at this key with the return value of calling updater with the existing value.

    Similar to: map.set(key, updater(map.get(key))).

    const { Map } = require('immutable')
    const aMap = Map({ key: 'value' })
    const newMap = aMap.update('key', value => value + value)
    // Map { "key": "valuevalue" }

    This is most commonly used to call methods on collections within a structure of data. For example, in order to .push() onto a nested List, update and push can be used together:

    const aMap = Map({ nestedList: List([ 1, 2, 3 ]) })
    const newMap = aMap.update('nestedList', list => list.push(4))
    // Map { "nestedList": List [ 1, 2, 3, 4 ] }

    When a notSetValue is provided, it is provided to the updater function when the value at the key does not exist in the Map.

    const aMap = Map({ key: 'value' })
    const newMap = aMap.update('noKey', 'no value', value => value + value)
    // Map { "key": "value", "noKey": "no valueno value" }

    However, if the updater function returns the same value it was called with, then no change will occur. This is still true if notSetValue is provided.

    const aMap = Map({ apples: 10 })
    const newMap = aMap.update('oranges', 0, val => val)
    // Map { "apples": 10 }
    assert.strictEqual(newMap, map);

    For code using ES2015 or later, using notSetValue is discourged in favor of function parameter default values. This helps to avoid any potential confusion with identify functions as described above.

    The previous example behaves differently when written with default values:

    const aMap = Map({ apples: 10 })
    const newMap = aMap.update('oranges', (val = 0) => val)
    // Map { "apples": 10, "oranges": 0 }

    If no key is provided, then the updater function return value is returned as well.

    const aMap = Map({ key: 'value' })
    const result = aMap.update(aMap => aMap.get('key'))
    // "value"

    This can be very useful as a way to "chain" a normal function into a sequence of methods. RxJS calls this "let" and lodash calls it "thru".

    For example, to sum the values in a Map

    function sum(collection) {
    return collection.reduce((sum, x) => sum + x, 0)
    }

    Map({ x: 1, y: 2, z: 3 })
    .map(x => x + 1)
    .filter(x => x % 2 === 0)
    .update(sum)
    // 6

    Note: update(key) can be used in withMutations.

    Parameters

    • key: K
    • notSetValue: V
    • updater: (value: V) => V
        • (value: V): V
        • Parameters

          • value: V

          Returns V

    Returns <internal>.OrderedMap<K, V>

  • Parameters

    • key: K
    • updater: (value: undefined | V) => V
        • (value: undefined | V): V
        • Parameters

          • value: undefined | V

          Returns V

    Returns <internal>.OrderedMap<K, V>

  • Type parameters

    • R

    Parameters

    Returns R

  • Returns a new Map having applied the updater to the entry found at the keyPath.

    This is most commonly used to call methods on collections nested within a structure of data. For example, in order to .push() onto a nested List, updateIn and push can be used together:

    const { Map, List } = require('immutable')
    const map = Map({ inMap: Map({ inList: List([ 1, 2, 3 ]) }) })
    const newMap = map.updateIn(['inMap', 'inList'], list => list.push(4))
    // Map { "inMap": Map { "inList": List [ 1, 2, 3, 4 ] } }

    If any keys in keyPath do not exist, new Immutable Maps will be created at those keys. If the keyPath does not already contain a value, the updater function will be called with notSetValue, if provided, otherwise undefined.

    const map = Map({ a: Map({ b: Map({ c: 10 }) }) })
    const newMap = map.updateIn(['a', 'b', 'c'], val => val * 2)
    // Map { "a": Map { "b": Map { "c": 20 } } }

    If the updater function returns the same value it was called with, then no change will occur. This is still true if notSetValue is provided.

    const map = Map({ a: Map({ b: Map({ c: 10 }) }) })
    const newMap = map.updateIn(['a', 'b', 'x'], 100, val => val)
    // Map { "a": Map { "b": Map { "c": 10 } } }
    assert.strictEqual(newMap, aMap)

    For code using ES2015 or later, using notSetValue is discourged in favor of function parameter default values. This helps to avoid any potential confusion with identify functions as described above.

    The previous example behaves differently when written with default values:

    const map = Map({ a: Map({ b: Map({ c: 10 }) }) })
    const newMap = map.updateIn(['a', 'b', 'x'], (val = 100) => val)
    // Map { "a": Map { "b": Map { "c": 10, "x": 100 } } }

    Plain JavaScript Object or Arrays may be nested within an Immutable.js Collection, and updateIn() can update those values as well, treating them immutably by creating new copies of those values with the changes applied.

    const map = Map({ a: { b: { c: 10 } } })
    const newMap = map.updateIn(['a', 'b', 'c'], val => val * 2)
    // Map { "a": { b: { c: 20 } } }

    If any key in the path exists but cannot be updated (such as a primitive like number or a custom Object like Date), an error will be thrown.

    Note: updateIn can be used in withMutations.

    Parameters

    • keyPath: Iterable<unknown>
    • notSetValue: unknown
    • updater: (value: unknown) => unknown
        • (value: unknown): unknown
        • Parameters

          • value: unknown

          Returns unknown

    Returns <internal>.OrderedMap<K, V>

  • Parameters

    • keyPath: Iterable<unknown>
    • updater: (value: unknown) => unknown
        • (value: unknown): unknown
        • Parameters

          • value: unknown

          Returns unknown

    Returns <internal>.OrderedMap<K, V>

  • Returns an Seq.Indexed of the values of this Collection, discarding keys.

    Returns <internal>.Indexed<V>

  • An iterator of this Collection's values.

    Note: this will return an ES6 iterator which does not support Immutable.js sequence algorithms. Use valueSeq instead, if this is what you want.

    Returns IterableIterator<V>

  • wasAltered(): boolean
  • Returns true if this is a mutable copy (see asMutable()) and mutative alterations have been applied.

    see

    Map#asMutable

    Returns boolean

  • Every time you call one of the above functions, a new immutable Map is created. If a pure function calls a number of these to produce a final return value, then a penalty on performance and memory has been paid by creating all of the intermediate immutable Maps.

    If you need to apply a series of mutations to produce a new immutable Map, withMutations() creates a temporary mutable copy of the Map which can apply mutations in a highly performant manner. In fact, this is exactly how complex mutations like merge are done.

    As an example, this results in the creation of 2, not 4, new Maps:

    const { Map } = require('immutable')
    const map1 = Map()
    const map2 = map1.withMutations(map => {
    map.set('a', 1).set('b', 2).set('c', 3)
    })
    assert.equal(map1.size, 0)
    assert.equal(map2.size, 3)

    Note: Not all methods can be used on a mutable collection or within withMutations! Read the documentation for each method to see if it is safe to use in withMutations.

    Parameters

    Returns <internal>.OrderedMap<K, V>

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