Returns a new Collection of the same type containing all entries except the last.
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.
Optionalcontext: unknownAn 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.
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.
True if predicate returns true for all entries in the Collection.
Optionalcontext: unknownReturns a new Collection of the same type 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.
Optionalcontext: unknownReturns a new Collection of the same type with only the entries for which
the predicate function returns false.
Note: filterNot() always returns a new instance, even if it results in
not filtering out any values.
Optionalcontext: unknownReturns the first index in the Collection where a value satisfies the provided predicate function. Otherwise -1 is returned.
Optionalcontext: unknownReturns the last index in the Collection where a value satisfies the provided predicate function. Otherwise -1 is returned.
Optionalcontext: unknownReturns the last key for which the predicate returns true.
Note: predicate will be called for each entry in reverse.
Optionalcontext: unknownFlattens 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>
Optionaldepth: numberOptionalshallow: booleanThe 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).
Optionalcontext: unknownIf this is a collection of [key, value] entry tuples, it will return a Seq.Keyed of those entries.
Returns the value associated with the provided index, or notSetValue if the index is beyond the bounds of the Collection.
index may be a negative number, which indexes back from the end of the
Collection. s.get(-1) gets the last item in the Collection.
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.
Returns the value found by following a path of keys or indices through nested Collections.
Plain JavaScript Object or Arrays may be nested within an Immutable.js Collection, and getIn() can access those values as well:
OptionalnotSetValue: unknownTrue if a key exists within this Collection, using Immutable.is
to determine equality
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.
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 the result of following a path of keys or indices through nested Collections results in a set value.
True if a value exists within this Collection, using Immutable.is
to determine equality
Returns the first index at which a given value can be found in the Collection, or -1 if it is not present.
Returns a Collection of the same type with the provided collections
interleaved into this collection.
The resulting Collection includes the first item from each, then the second from each, etc.
The shortest Collection stops interleave.
Since interleave() re-indexes values, it produces a complete copy,
which has O(N) complexity.
Note: interleave cannot be used in withMutations.
Returns a Collection of the same type with separator between each item
in this Collection.
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.
Joins values together as a string, inserting a separator between each.
The default separator is ",".
Optionalseparator: stringReturns the key associated with the search value, or undefined.
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 a new Seq.Indexed of the keys of this Collection, discarding values.
Returns the last index at which a given value can be found in the Collection, or -1 if it is not present.
Returns the last key associated with the search value, or undefined.
Returns a new Collection.Indexed with values passed through a
mapper function.
import { Collection } from 'immutable'
Collection.Indexed([1,2]).map(x => 10 * x)
// Seq [ 1, 2 ]
Note: map() always returns a new instance, even if it produced the
same value at every step.
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.
Optionalcomparator: Comparator<T>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.
Optionalcomparator: Comparator<T>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.
Returns a new Collection of the same type containing all entries except the first.
Returns a new Collection of the same type in reverse order.
Returns a new Collection of the same type which excludes the first amount
entries from this Collection.
Returns a new Collection of the same type which excludes the last amount
entries from this Collection.
Returns a new Collection of the same type which includes entries starting
from when predicate first returns true.
Optionalcontext: unknownReturns a new Collection of the same type which includes entries starting
from when predicate first returns false.
Optionalcontext: unknownReturns 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.
Optionalbegin: numberOptionalend: numberTrue if predicate returns true for any entry in the Collection.
Optionalcontext: unknownReturns 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):
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 valueBPairSorting enum typeWhen sorting collections which have no defined order, their ordered
equivalents will be returned. e.g. map.sort() returns OrderedMap.
Note: sort() Always returns a new instance, even if the original was
already sorted.
Note: This is always an eager operation.
Optionalcomparator: Comparator<T>Like sort, but also accepts a comparatorValueMapper which allows for
sorting by more sophisticated means:
Note: sortBy() Always returns a new instance, even if the original was
already sorted.
Note: This is always an eager operation.
Splice returns a new indexed Collection by replacing a region of this Collection with new values. If values are not provided, it only skips the region to be removed.
index may be a negative number, which indexes back from the end of the
Collection. s.splice(-2) splices after the second to last item.
Since splice() re-indexes values, it produces a complete copy, which
has O(N) complexity.
Note: splice cannot be used in withMutations.
Returns a new Collection of the same type which includes the first amount
entries from this Collection.
Returns a new Collection of the same type which includes the last amount
entries from this Collection.
Returns a new Collection of the same type which includes entries from this
Collection as long as the predicate returns false.
Optionalcontext: unknownReturns a new Collection of the same type which includes entries from this
Collection as long as the predicate returns true.
Optionalcontext: unknownShallowly converts this collection to an Array.
Deeply converts this Indexed collection to equivalent native JavaScript Array.
Shallowly converts this Indexed collection to equivalent native JavaScript Array.
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.
Shallowly converts this Collection to an Object.
Converts keys to Strings.
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.
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.
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 a Collection of the same type "zipped" with the provided collections.
Like zipWith, but using the default zipper: creating an Array.
Returns a Collection "zipped" with the provided collections.
Unlike zip, zipAll continues zipping until the longest collection is
exhausted. Missing values from shorter collections are filled with undefined.
const a = List([ 1, 2 ]);
const b = List([ 3, 4, 5 ]);
const c = a.zipAll(b); // List [ [ 1, 3 ], [ 2, 4 ], [ undefined, 5 ] ]
The interface to fulfill to qualify as a Value Object.