Interface Set<T>

For Seqs, all entries will be present in the resulting iterable, even if they have the same key.

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.

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

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

Seq({a:1,b:2,c:3,d:4}).filter(x => x % 2 === 0)
// Seq { b: 2, d: 4 }

Seq({a:1,b:2,c:3,d:4}).filterNot(x => x % 2 === 0)
// Seq { a: 1, c: 3 }

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

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

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

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>

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).

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.

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.

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

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 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.

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.

Seq.of('dog','frog','cat','hat','god')
  .skipUntil(x => x.match(/hat/))
// Seq [ 'hat', 'god' ]

Seq.of('dog','frog','cat','hat','god')
  .skipWhile(x => x.match(/g/))
// Seq [ 'cat', 'hat', 'god' ]

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.

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.

Seq.of('dog','frog','cat','hat','god').takeUntil(x => x.match(/at/))
// ['dog', 'frog']

Seq.of('dog','frog','cat','hat','god')
  .takeWhile(x => x.match(/o/))
// Seq [ 'dog', 'frog' ]

Iterable.Indexeds, and Iterable.Sets become Arrays, while Iterable.Keyeds become Objects.

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' }

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

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

Throws if keys are not strings.

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

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

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

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

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