The yin to asMutable's yang. Because it applies to mutable collections,
this operation is mutable and returns itself. Once performed, the mutable
copy has become immutable and can be safely returned from a function.
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 as it provides an easier to
use API.
Note: if the collection is already mutable, asMutable returns itself.
Note: Not all methods can be used on a mutable collection or within
withMutations! Only set and merge may be used mutatively.
Returns a new Iterable of the same type containing all entries except the last.
Returns a new Map containing no keys or values.
Returns a new Iterable of the same type with other values and iterable-like concatenated to this one.
For Seqs, all entries will be present in the resulting iterable, even if they have the same key.
Returns the size of this Iterable.
Regardless of if this Iterable 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
Iterable for which the predicate returns true.
Returns a Seq.Keyed of counts, grouped by the return value of
the grouper function.
Note: This is not a lazy operation.
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.
Returns a new Map having removed the value at this keyPath. If any keys
in keyPath do not exist, no change will occur.
An iterator of this Iterable'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 a new Seq.Indexed of [key, value] tuples.
True if this and the other Iterable have value equality, as defined
by Immutable.is().
Note: This is equivalent to Immutable.is(this, other), but provided to
allow for chained expressions.
True if predicate returns true for all entries in the Iterable.
Returns a new Iterable of the same type with only the entries for which
the predicate function returns true.
Seq({a:1,b:2,c:3,d:4}).filter(x => x % 2 === 0)
// Seq { b: 2, d: 4 }
Returns a new Iterable of the same type with only the entries for which
the predicate function returns false.
Seq({a:1,b:2,c:3,d:4}).filterNot(x => x % 2 === 0)
// Seq { a: 1, c: 3 }
Returns the first value for which the predicate returns true.
Returns the first [key, value] entry for which the predicate returns true.
Returns the key for which the predicate returns true.
Returns the last value for which the predicate returns true.
Note: predicate will be called for each entry in reverse.
Returns the last [key, value] entry for which the predicate
returns true.
Note: predicate will be called for each entry in reverse.
Returns the last key for which the predicate returns true.
Note: predicate will be called for each entry in reverse.
The first value in the Iterable.
Flat-maps the Iterable, returning an Iterable of the same type.
Similar to iter.map(...).flatten(true).
Flattens nested Iterables.
Will deeply flatten the Iterable by default, returning an Iterable 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 Iterable, not Arrays or Objects.
Note: flatten(true) operates on Iterable<any, Iterable<K, V>> and
returns Iterable<K, V>
Returns a new Iterable.Keyed of the same type where the keys and values have been flipped.
Seq({ a: 'z', b: 'y' }).flip() // { z: 'a', y: 'b' }
The sideEffect is executed for every entry in the Iterable.
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).
Returns the value associated with the provided key, or notSetValue if the Iterable 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.
Returns the value found by following a path of keys or indices through nested Iterables.
Returns a Iterable.Keyed of Iterable.Keyeds, grouped by the return
value of the grouper function.
Note: This is always an eager operation.
True if a key exists within this Iterable, using Immutable.is to determine equality
True if the result of following a path of keys or indices through nested Iterables results in a set value.
Computes and returns the hashed identity for this Iterable.
The hashCode of an Iterable 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.
var a = List.of(1, 2, 3);
var b = List.of(1, 2, 3);
assert(a !== b); // different instances
var set = Set.of(a);
assert(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.
True if a value exists within this Iterable, using Immutable.is to determine equality
Returns true if this Iterable includes no values.
For some lazy Seq, isEmpty might need to iterate to determine
emptiness. At most one iteration will occur.
True if iter includes every value in this Iterable.
True if this Iterable includes every value in iter.
Joins values together as a string, inserting a separator between each.
The default separator is ",".
Returns the key associated with the search value, or undefined.
Returns a new Seq.Indexed of the keys of this Iterable, discarding values.
An iterator of this Iterable'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.
The last value in the Iterable.
Returns the last key associated with the search value, or undefined.
Returns a new Iterable of the same type with values passed through a
mapper function.
Seq({ a: 1, b: 2 }).map(x => 10 * x)
// Seq { a: 10, b: 20 }
Returns a new Iterable.Keyed of the same type with entries
([key, value] tuples) passed through a mapper function.
Seq({ a: 1, b: 2 })
.mapEntries(([k, v]) => [k.toUpperCase(), v * 2])
// Seq { A: 2, B: 4 }
Returns a new Iterable.Keyed of the same type with keys passed through
a mapper function.
Seq({ a: 1, b: 2 })
.mapKeys(x => x.toUpperCase())
// Seq { A: 1, B: 2 }
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 Iterable#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.
Like max, but also accepts a comparatorValueMapper which allows for
comparing by more sophisticated means:
hitters.maxBy(hitter => hitter.avgHits);
Returns a new Map resulting from merging the provided Iterables (or JS objects) into this Map. In other words, this takes each entry of each iterable and sets it on this Map.
If any of the values provided to merge are not Iterable (would return
false for Immutable.Iterable.isIterable) then they are deeply converted
via Immutable.fromJS before being merged. However, if the value is an
Iterable but includes non-iterable JS objects or arrays, those nested
values will be preserved.
var x = Immutable.Map({a: 10, b: 20, c: 30});
var y = Immutable.Map({b: 40, a: 50, d: 60});
x.merge(y) // { a: 50, b: 40, c: 30, d: 60 }
y.merge(x) // { b: 20, a: 10, d: 60, c: 30 }
Like merge(), but when two Iterables conflict, it merges them as well,
recursing deeply through the nested data.
var x = Immutable.fromJS({a: { x: 10, y: 10 }, b: { x: 20, y: 50 } });
var y = Immutable.fromJS({a: { x: 2 }, b: { y: 5 }, c: { z: 3 } });
x.mergeDeep(y) // {a: { x: 2, y: 10 }, b: { x: 20, y: 5 }, c: { z: 3 } }
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:
x.updateIn(['a', 'b', 'c'], abc => abc.mergeDeep(y));
x.mergeDeepIn(['a', 'b', 'c'], y);
Like mergeDeep(), but when two non-Iterables conflict, it uses the
merger function to determine the resulting value.
var x = Immutable.fromJS({a: { x: 10, y: 10 }, b: { x: 20, y: 50 } });
var y = Immutable.fromJS({a: { x: 2 }, b: { y: 5 }, c: { z: 3 } });
x.mergeDeepWith((prev, next) => prev / next, y)
// {a: { x: 5, y: 10 }, b: { x: 20, y: 10 }, c: { z: 3 } }
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:
x.updateIn(['a', 'b', 'c'], abc => abc.merge(y));
x.mergeIn(['a', 'b', 'c'], y);
Like merge(), mergeWith() returns a new Map resulting from merging
the provided Iterables (or JS objects) into this Map, but uses the
merger function for dealing with conflicts.
var x = Immutable.Map({a: 10, b: 20, c: 30});
var y = Immutable.Map({b: 40, a: 50, d: 60});
x.mergeWith((prev, next) => prev / next, y) // { a: 0.2, b: 0.5, c: 30, d: 60 }
y.mergeWith((prev, next) => prev / next, x) // { b: 2, a: 5, d: 60, c: 30 }
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 Iterable#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.
Like min, but also accepts a comparatorValueMapper which allows for
comparing by more sophisticated means:
hitters.minBy(hitter => hitter.avgHits);
Reduces the Iterable to a value by calling the reducer for every entry
in the Iterable and passing along the reduced value.
If initialReduction is not provided, or is null, the first item in the
Iterable will be used.
Reduces the Iterable in reverse (from the right side).
Note: Similar to this.reverse().reduce(), and provided for parity
with Array#reduceRight.
Returns a new Iterable of the same type containing all entries except the first.
Returns a new Iterable of the same type in reverse order.
Returns a new Map also containing the new key, value pair. If an equivalent key already exists in this Map, it will be replaced.
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.
Returns a new Iterable of the same type which excludes the first amount
entries from this Iterable.
Returns a new Iterable of the same type which excludes the last amount
entries from this Iterable.
Returns a new Iterable of the same type which includes entries starting
from when predicate first returns true.
Seq.of('dog','frog','cat','hat','god')
.skipUntil(x => x.match(/hat/))
// Seq [ 'hat', 'god' ]
Returns a new Iterable of the same type which includes entries starting
from when predicate first returns false.
Seq.of('dog','frog','cat','hat','god')
.skipWhile(x => x.match(/g/))
// Seq [ 'cat', 'hat', 'god' ]
Returns a new Iterable of the same type representing a portion of this Iterable from start up to but not including end.
If begin is negative, it is offset from the end of the Iterable. e.g.
slice(-2) returns a Iterable of the last two entries. If it is not
provided the new Iterable will begin at the beginning of this Iterable.
If end is negative, it is offset from the end of the Iterable. e.g.
slice(0, -1) returns an Iterable of everything but the last entry. If
it is not provided, the new Iterable will continue through the end of
this Iterable.
If the requested slice is equivalent to the current Iterable, then it will return itself.
True if predicate returns true for any entry in the Iterable.
Returns a new Iterable 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):
0 if the elements should not be swapped.-1 (or any negative number) if valueA comes before valueB1 (or any positive number) if valueA comes after valueBWhen sorting collections which have no defined order, their ordered
equivalents will be returned. e.g. map.sort() returns OrderedMap.
Like sort, but also accepts a comparatorValueMapper which allows for
sorting by more sophisticated means:
hitters.sortBy(hitter => hitter.avgHits);
Returns a new Iterable of the same type which includes the first amount
entries from this Iterable.
Returns a new Iterable of the same type which includes the last amount
entries from this Iterable.
Returns a new Iterable of the same type which includes entries from this
Iterable as long as the predicate returns false.
Seq.of('dog','frog','cat','hat','god').takeUntil(x => x.match(/at/))
// ['dog', 'frog']
Returns a new Iterable of the same type which includes entries from this
Iterable as long as the predicate returns true.
Seq.of('dog','frog','cat','hat','god')
.takeWhile(x => x.match(/o/))
// Seq [ 'dog', 'frog' ]
Shallowly converts this iterable to an Array, discarding keys.
Returns an Seq.Indexed of the values of this Iterable, discarding keys.
Deeply converts this Iterable to equivalent JS.
Iterable.Indexeds, and Iterable.Sets become Arrays, while
Iterable.Keyeds become Objects.
Returns a Seq.Keyed from this Iterable where indices are treated as keys.
This is useful if you want to operate on an Iterable.Indexed and preserve the [index, value] pairs.
The returned Seq will have identical iteration order as this Iterable.
Example:
var indexedSeq = Immutable.Seq.of('A', 'B', 'C');
indexedSeq.filter(v => v === 'B').toString() // Seq [ 'B' ]
var keyedSeq = indexedSeq.toKeyedSeq();
keyedSeq.filter(v => v === 'B').toString() // Seq { 1: 'B' }
Converts this Iterable to a List, discarding keys.
Note: This is equivalent to List(this), but provided to allow
for chained expressions.
Converts this Iterable 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.
Shallowly converts this Iterable to an Object.
Throws if keys are not strings.
Converts this Iterable 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.
Converts this Iterable 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 Seq.Keyed.
Converts this Iterable 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 a Seq.Set of the values of this Iterable, discarding keys.
Converts this Iterable 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 a new Map having updated the value at this key with the return
value of calling updater with the existing value, or notSetValue if
the key was not set. If called with only a single argument, updater is
called with the Map itself.
Equivalent to: map.set(key, updater(map.get(key, notSetValue))).
Returns a new Map having applied the updater to the entry found at the
keyPath.
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.
var data = Immutable.fromJS({ a: { b: { c: 10 } } });
data = data.updateIn(['a', 'b', 'c'], val => val * 2);
// { a: { b: { 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.
var data1 = Immutable.fromJS({ a: { b: { c: 10 } } });
data2 = data1.updateIn(['x', 'y', 'z'], 100, val => val);
assert(data2 === data1);
Returns an Seq.Indexed of the values of this Iterable, discarding keys.
An iterator of this Iterable'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.
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:
var map1 = Immutable.Map();
var map2 = map1.withMutations(map => {
map.set('a', 1).set('b', 2).set('c', 3);
});
assert(map1.size === 0);
assert(map2.size === 3);
Note: Not all methods can be used on a mutable collection or within
withMutations! Only set and merge may be used mutatively.
Generated using TypeDoc
All collections maintain their current
sizeas an integer.