Readonly
sizeReturns 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.
Optional
context: unknownReturns a Seq.Keyed
of counts, grouped by the return value of
the grouper
function.
Note: This is not a lazy operation.
Optional
context: unknownTrue if predicate
returns true for all entries in the Collection.
Optional
context: unknownReturns a new Set with only the values for which the predicate
function returns true.
Note: filter()
always returns a new instance, even if it results in
not filtering out any values.
Optional
context: unknownOptional
context: unknownReturns 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.
Optional
context: unknownReturns the first value for which the predicate
returns true.
Optional
context: unknownOptional
notSetValue: TReturns the first [key, value] entry for which the predicate
returns true.
Optional
context: unknownOptional
notSetValue: TReturns the key for which the predicate
returns true.
Optional
context: unknownReturns the last value for which the predicate
returns true.
Note: predicate
will be called for each entry in reverse.
Optional
context: unknownOptional
notSetValue: TReturns the last [key, value] entry for which the predicate
returns true.
Note: predicate
will be called for each entry in reverse.
Optional
context: unknownOptional
notSetValue: TReturns the last key for which the predicate
returns true.
Note: predicate
will be called for each entry in reverse.
Optional
context: unknownIn 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.
Optional
notSetValue: NSVFlat-maps the Set, returning a new Set.
Similar to set.map(...).flatten(true)
.
Optional
context: 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>
Optional
depth: numberOptional
shallow: 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).
Optional
context: unknownReturns a sequence representing a subset of this sorted set starting with value up to the last element in the set.
If the optional parameter backwards is set to true, the returned sequence will list the entries backwards, starting with value down to the first element in the set.
Example:
const { SortedSet } = require('@oraichain/immutable');
const abc = SortedSet(["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"]);
> abc.from("R");
Seq { "R", "S", "T", "U", "V", "W", "X", "Y", "Z" }
> abc.from("R", true);
Seq { "R", "Q", "P", "O", "N", "M", "L", "K", "J", "I", "H", "G", "F", "E", "D", "C", "B", "A" }
The method from() can be efficiently combined with take() to retrieve the desired number of values or with takeWhile() to retrieve a specific range:
> abc.from("R").take(5);
Seq { "R", "S", "T", "U", "V" }
> abc.from("R").takeWhile(s => s < "W");
Seq { "R", "S", "T", "U", "V" }
> abc.from("R", true).take(5);
Seq { "R", "Q", "P", "O", "N" }
> abc.from("R", true).takeWhile(s => s > "K");
Seq { "R", "Q", "P", "O", "N", "M", "L" }
Optional
backwards: booleanReturns a sequence representing a portion of this sorted set starting from numeric index position, as if the collection was an array. If the optional parameter backwards is set to true, the returned sequence will list the entries backwards.
The method is optimized to quickly find the n-th entry inside the b-tree structure by checking the computed sizes of underlying nodes. Even though the algorithm is not as fast as working with a native array, it is faster by orders of magnitude than walking through the first n elements of unindexed collection to just skip them. The access time is O(log N).
Example:
> abc.fromIndex(4).take(5);
Seq { "E", "F", "G", "H", "I" }
> abc.fromIndex(4, true).take(5);
Seq { "E", "D", "C", "B", "A" }
Optional
backwards: booleanReturns 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.
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
Optional
notSetValue: unknownReturns a Map
of Collection
, 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 } ],
// }
Optional
context: unknownComputes 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 hashCode
s,
they must not be equal.
The incremental sort optimized to provide first entries of the result set faster than regular sort(). Similarly to partialSort() it is using the Floyd-Rivest select algorithm. The incremental sort doesn't cache its results as it is supposed to be used with iterators retrieving limited number of result entries.
Optional
comparator: ((valueA, valueB) => number)Like incSort
, but also accepts a comparatorValueMapper
which allows for
sorting by more sophisticated means:
hitters.incSortBy(hitter => hitter.avgHits)
Optional
comparator: ((valueA, valueB) => number)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.
Optional
notSetValue: NSVReturns a new Set with values passed through a
mapper
function.
Set([1,2]).map(x => 10 * x)
// Set [10,20]
Optional
context: unknownReturns 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.
Optional
comparator: Comparator<T>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 }
Optional
comparator: Comparator<C>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.
Optional
comparator: Comparator<T>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 }
Optional
comparator: Comparator<C>Returns a new SortedSet
containing the values of the provided
collection-like. The values will be organized in an optimized tree structure
with internal nodes and leaves defragmented as much as possible
while keeping all the consistency rules enforced.
If the collection argument is undefined then the current content
of this SortedSet
will be reorganized into an optimized tree structure.
The pack procedure is actually called from the SortedSet
constructor
as it is usually faster than a series of add operations. It is recommended
to explicitly call this method after a large batch of add or delete operations
to release a portion of the allocated memory and to speed up the consequent get
operations.
Optional
collection: Iterable<T>Efficiently sorting the first N items in the collection using the Floyd-Rivest select algorithm.
Optional
comparator: ((valueA, valueB) => number)Like partialSort
, but also accepts a comparatorValueMapper
which allows for
sorting by more sophisticated means:
hitters.partialSortBy(10, hitter => hitter.avgHits)
Optional
comparator: ((valueA, valueB) => number)Returns a new Set with the values for which the predicate
function
returns false and another for which is returns true.
Optional
context: COptional
context: CReduces 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.
Array#reduce
.
Optional
context: unknownReduces the Collection in reverse (from the right side).
Note: Similar to this.reverse().reduce(), and provided for parity
with Array#reduceRight
.
Optional
context: unknownReturns 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" ]
Optional
context: unknownReturns 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" ]
Optional
context: 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.
Optional
begin: numberOptional
end: numberTrue if predicate
returns true for any entry in the Collection.
Optional
context: 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 valueB
1
(or any positive number) if valueA
comes after valueB
PairSorting
enum typeWhen 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.
Optional
comparator: Comparator<T>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.
Optional
comparator: Comparator<C>Returns a Set excluding any values contained within collections
.
const { OrderedSet } = require('immutable')
OrderedSet([ 1, 2, 3 ]).subtract([1, 3])
// OrderedSet [2]
Note: subtract
can be used in withMutations
.
Rest
...collections: Iterable<T>[]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" ]
Optional
context: unknownReturns 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" ]
Optional
context: unknownReturns 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" }
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" ]
Converts this Collection to a SortedMap, with entries sorted according to comparator
If comparator is undefined then defaultComparator
will be applied.
Note: This is equivalent to SortedMap(this.toKeyedSeq())
, but
provided for convenience and to allow for chained expressions.
Optional
comparator: ((a, b) => number)Optional
options: { Converts this Collection to a SortedSet, maintaining the order of iteration and discarding keys.
Note: This is equivalent to SortedSet(this.valueSeq())
, but provided
for convenience and to allow for chained expressions.
Optional
comparator: ((a, b) => number)Optional
options: { 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 a Seq after mapping and filtering:
const { Seq } = require('immutable')
function sum(collection) {
return collection.reduce((sum, x) => sum + x, 0)
}
Seq([ 1, 2, 3 ])
.map(x => x + 1)
.filter(x => x % 2 === 0)
.update(sum)
// 6
Note: Not all methods can be used on a mutable collection or within
withMutations
! Check the documentation for each method to see if it
mentions being safe to use in withMutations
.
Map#withMutations
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The number of items in this SortedSet.