the item type
Used by the node REPL to display values. Most of the time should be the same as toString()
Returns true if the predicate returns true for all the elements in the collection.
Returns true if there the predicate returns true for any element in the collection.
Append an element at the end of the collection.
Append multiple elements at the end of the collection. Note that arrays are also iterables.
Matches each element with a unique key that you extract from it. If the same key is present twice, the function will return None.
also see Collection.groupBy
Returns true if the item is in the collection, false otherwise.
Remove duplicate items; elements are mapped to keys, those get compared.
Vector.of(1,1,2,3,2,3,1).distinctBy(x => x);
=> Vector.of(1,2,3)
Returns a new collection with the first n elements discarded. If the collection has less than n elements, returns the empty collection.
Returns a new collection with the last n elements discarded. If the collection has less than n elements, returns the empty collection.
Returns a new collection, discarding the last elements until one element fails the predicate. All elements before that point are retained.
Returns a new collection, discarding the first elements until one element fails the predicate. All elements after that point are retained.
Two objects are equal if they represent the same value, regardless of whether they are the same object physically in memory.
Call a predicate for each element in the collection, build a new collection holding only the elements for which the predicate returned true.
Search for an item matching the predicate you pass, return Option.Some of that element if found, Option.None otherwise.
Reduces the collection to a single value using the associative binary function you give. Since the function is associative, order of application doesn't matter.
Example:
HashSet.of(1,2,3).fold(0, (a,b) => a + b);
=> 6
Reduces the collection to a single value. Left-associative.
Example:
Vector.of("a", "b", "c").foldLeft("!", (xs,x) => x+xs);
=> "cba!"
The initial value
A function taking the previous value and the current collection item, and returning an updated value.
Reduces the collection to a single value. Right-associative.
Example:
Vector.of("a", "b", "c").foldRight("!", (x,xs) => xs+x)
=> "!cba"
The initial value
A function taking the current collection item and the previous value , and returning an updated value.
Call a function for element in the collection. Return the unchanged collection.
Retrieve the element at index idx. Returns an option because the collection may contain less elements than the index.
Group elements in the collection using a classifier function. Elements are then organized in a map. The key is the value of the classifier, and in value we get the list of elements matching that value.
also see Collection.arrangeBy
Get a number for that object. Two different values may get the same number, but one value must always get the same number. The formula can impact performance.
Get the first value of the collection, if any. returns Option.Some if the collection is not empty, Option.None if it's empty.
true if the collection is empty, false otherwise.
Get the last value of the collection, if any. returns Option.Some if the collection is not empty, Option.None if it's empty.
Get the length of the collection.
Return a new collection where each element was transformed by the mapper function you give.
Apply the mapper function on every element of this collection. The mapper function returns an Option; if the Option is a Some, the value it contains is added to the result Collection, if it's a None, the value is discarded.
Vector.of(1,2,6).mapOption(x => x%2===0 ?
Option.of(x+1) : Option.none<number>())
=> Vector.of(3, 7)
Compare values in the collection and return the largest element. Returns Option.none if the collection is empty.
also see Collection.maxOn
Call the function you give for each value in the collection and return the element for which the result was the largest. Returns Option.none if the collection is empty.
Vector.of({name:"Joe", age:12}, {name:"Paula", age:6}).maxOn(x=>x.age)
=> Option.of({name:"Joe", age:12})
also see Collection.maxBy
Compare values in the collection and return the smallest element. Returns Option.none if the collection is empty.
also see Collection.minOn
Call the function you give for each value in the collection and return the element for which the result was the smallest. Returns Option.none if the collection is empty.
Vector.of({name:"Joe", age:12}, {name:"Paula", age:6}).minOn(x=>x.age)
=> Option.of({name:"Paula", age:6})
also see Collection.minBy
Joins elements of the collection by a separator. Example:
Vector.of(1,2,3).mkString(", ")
=> "1, 2, 3"
Returns a pair of two collections; the first one will only contain the items from this collection for which the predicate you give returns true, the second will only contain the items from this collection where the predicate returns false.
Vector.of(1,2,3,4).partition(x => x%2===0)
=> [Vector.of(2,4), Vector.of(1,3)]
Prepend an element at the beginning of the collection.
Prepend multiple elements at the beginning of the collection.
Reduces the collection to a single value by repeatedly calling the combine function. No starting value. The order in which the elements are passed to the combining function is undetermined.
Remove multiple elements from a collection
Vector.of(1,2,3,4,3,2,1).removeAll([2,4])
=> Vector.of(1,3,3,1)
Removes the first element matching the predicate (use Seq.filter to remove all elements matching a predicate)
Reverse the collection. For instance:
Vector.of(1,2,3).reverse();
=> Vector.of(3,2,1)
Apply the function you give to all elements of the sequence in turn, keeping the intermediate results and returning them along with the final result in a list. The last element of the result is the final cumulative result.
Vector.of(1,2,3).scanLeft(0, (cur,soFar)=>soFar+cur)
=> Vector.of(0,1,3,6)
Apply the function you give to all elements of the sequence in turn, keeping the intermediate results and returning them along with the final result in a list. The first element of the result is the final cumulative result.
Vector.of(1,2,3).scanRight(0, (cur,soFar)=>soFar+cur)
=> Vector.of(6,5,3,0)
Randomly reorder the elements of the collection.
If the collection contains a single element, return Some of its value, otherwise return None.
Returns a new collection with elements sorted according to the comparator you give.
const activityOrder = ["Writer", "Actor", "Director"];
Vector.of({name:"George", activity: "Director"}, {name:"Robert", activity: "Actor"})
.sortBy((p1,p2) => activityOrder.indexOf(p1.activity) - activityOrder.indexOf(p2.activity));
=> Vector.of({"name":"Robert","activity":"Actor"}, {"name":"George","activity":"Director"})
also see Seq.sortOn
Give a function associating a number or a string with elements from the collection, and the elements are sorted according to that value.
Vector.of({a:3,b:"b"}, {a:1,b:"test"}, {a:2,b:"a"}).sortOn(elt=>elt.a)
=> Vector.of({a:1,b:"test"}, {a:2,b:"a"}, {a:3,b:"b"})
You can also sort by multiple criteria, and request 'descending' sorting:
Vector.of({a:1,b:"b"}, {a:1,b:"test"}, {a:2,b:"a"}).sortOn(elt=>elt.a, {desc:elt=>elt.b})
=> Vector.of({a:1,b:"test"}, {a:1,b:"b"}, {a:2,b:"a"})
also see Seq.sortBy
Takes a predicate; returns a pair of collections. The first one is the longest prefix of this collection which satisfies the predicate, and the second collection is the remainder of the collection.
Vector.of(1,2,3,4,5,6).span(x => x <3) => [Vector.of(1,2), Vector.of(3,4,5,6)]
Call the function you give for each element in the collection and sum all the numbers, return that sum. Will return 0 if the collection is empty.
Vector.of(1,2,3).sumOn(x=>x)
=> 6
Return a new collection containing the first n elements from this collection
Vector.of(1,2,3,4).take(2)
=> Vector.of(1,2)
Returns a new collection, discarding the elements after the first element which fails the predicate, but starting from the end of the collection.
Vector.of(1,2,3,4).takeRightWhile(x => x > 2)
=> Vector.of(3,4)
Returns a new collection, discarding the elements after the first element which fails the predicate.
Convert to array.
Convert this collection to a map. You give a function which for each element in the collection returns a pair. The key of the pair will be used as a key in the map, the value, as a value in the map. If several values get the same key, entries will be lost.
Vector.of(1,2,3).toMap(x=>[x.toString(), x])
=> HashMap.of(["1",1], ["2",2], ["3",3])
Convert this collection to a set. Since the elements of the Seq may not support equality, you must pass a function returning a value supporting equality.
Vector.of(1,2,3,3,4).toSet(x=>x)
=> HashSet.of(1,2,3,4)
Get a human-friendly string representation of that value.
Transform this value to another value type. Enables fluent-style programming by chaining calls.
Combine this collection with the collection you give in parameter to produce a new collection which combines both, in pairs. For instance:
Vector.of(1,2,3).zip(["a","b","c"])
=> Vector.of([1,"a"], [2,"b"], [3,"c"])
The result collection will have the length of the shorter of both collections. Extra elements will be discarded.
Also see Vector.zip, LinkedListStatic.zip and StreamStatic.zip (static versions which can more than two iterables)
Combine this collection with the index of the elements in it. Handy if you need the index when you map on the collection for instance:
Vector.of("a","b").zipWithIndex().map(([v,idx]) => v+idx);
=> Vector.of("a0", "b1")
Generated using TypeDoc
A generic interface for list-like implementations.