List

An ordered list of values.

A List is backed by a doubly linked list with a head node.

The list has a head property to an empty node. The list begins with the next node from the head. The last node of the list is the prev node from the head. The head represents the node one past the end of the list and has no value.

Nodes can be manipulated directly. Lists use a Node(value) property as their node constructor. It supports delete(), addBefore(node), and addAfter(node). Directly manipulating next and prev of a node allows for fast splicing.

Nodes can be reused to avoid garbage collector churn. However, if you do not need to splice, a Deque may perform better than List.

Lists can be iterated. The iterator will produce artificial indexes for each value.

Lists provide slow random access by index. Methods that accept indexes to seek a position will count as they walk to the sought node. These methods will always accept a node instead to instantly traverse to a known position.

Lists provide range change listeners, but at significant cost. Making range changes observable on a list requires that for each change to the list, it must scan back to the head of the list to determine the node’s index, which obviates the principle advantage of using the linked list structure. Also, direct manipulation of the nodes is not observable and will require manual change dispatch.

Properties

length: The number of items in this collection.

Methods

push(...values): Adds values to the end of a collection.
pop(): Removes a value from the end of a collection, and returns that value.
shift(): Removes a value from the beginning of a collection, and returns that value.
unshift(...values): Adds values to the beginning of a collection.
peek(): Returns the value at the beginning of a collection, the value that would be returned by shift().
poke(value): Replaces the value at the beginning of a collection, the value that would be returned by shift().
has(value): Whether an equivalent value exists in this collection.
has(value, equals?): Returns whether an equivalent value exists in this collection.
get(value): Retrieves the equivalent value from the collection.
get(value, equals?): Retrieves the equivalent value from this collection.
add(value): Adds a value to a collection.
delete(value): Deletes the first equivalent value. Returns whether the key was found and successfully deleted.
delete(value, equals?): Seeks out and deletes an equivalent value. Returns whether the value was found and successfully deleted.
addEach(values|map): Copies values or entries from another collection into this collection, and then returns this.
deleteEach(values|keys, equals?): Deletes every value or every value for each key. Returns the number of successful deletions.
deleteAll(value, equals?): Deletes every value equivalent to the given value from the collection.
slice(start?, end?): Returns an array of the values contained in the half-open interval [start, end), that is, including the start and excluding the end.
splice(start, length, ...values): Replaces a length of values from a starting position with the given variadic values, and returns the values that were replaced as an array.
swap(start, length, values?): Replaces a length of values from a starting position with the given values.
clear(): Deletes all of the values in the collection.
find(value, equals?, start?): Finds the first equivalent value.
findValue(value, equals?, start?): Finds the first equivalent value.
findLast(value, equals?, start?): Finds the last equivalent value, searching from the right.
findLastValue(value, equals?, start?): Finds the last equivalent value, searching from the right.
iterate|iterator(): Iterates every value in this collection.
forEach(callback, thisp?): Calls the callback for each entry in the collection.
map(callback, thisp?): Returns an array of the respective return values of a callback for each entry in this collection.
filter(callback, thisp?): Returns an array with each value from this collection that passes the given test.
reduce(callback, basis): Aggregates every value in this collection with the result collected up to that index.
reduceRight(callback, basis): Aggregates every value in this collection, from right to left.
group(callback, thisp?, equals?): Returns an array of [key, class] entries where every value from the collection is placed into the same equivalence class if they return the same key through the given callback.
some(callback, thisp?): Returns whether any entry in this collection passes a given test.
every(callback, thisp?): Returns whether every entry in this collection passes a given test.
any(): Returns whether any value in the collection is truthy.
all(): Returns whether all values in the collection are truthy.
one(): Returns one, arbitrary value from this collection, or undefined if there are none.
only(): Returns the only value in this collection, or undefined if there is more than one value, or if there are no values in the collection.
sort(compare?): Sorts a collection in place.
sorted(compare?): Returns a sorted array of the values in this collection.
reverse(): Reverses the order of this collection in place.
reversed(): Returns a copy of this collection with the values in reverse order.
join(delimiter?): Returns a string of all the values in the collection delimited by the given string.
sum(zero?): Returns the sum of all values in this collection.
average(): Returns the arithmetic mean of the collection, by computing its sum and the count of values and returning the quotient.
min(): Returns the smallest value in this collection.
max(): Returns the largest value in this collection.
zip(...iterables): Returns an array of the respective values in this collection and in each collection provided as an argument.
enumerate(start?): Returns an array of [index, value] entries for each value in this collection, counting all values from the given index.
concat(...iterables): Returns a new collection of the same type containing all the values of itself and the values of any number of other iterable collections in order.
flatten(): Assuming that this is a collection of collections, returns a new collection that contains all the values of each nested collection in order.
toArray(): Returns an array of each value in this collection.
toObject(): Returns an object with each property name and value corresponding to the entries in this collection.
toJSON(): Used by JSON.stringify to create a JSON representation of the collection.
equals(value, equals?): Returns whether this collection is equivalent to the given collection.
compare(value, compare?): Compares two values and returns a number having the same relative value to zero.
clone(depth?, memo?): Creates a deep replica of this collection.
constructClone(values?): Creates a shallow clone of this collection.
scan(index, default): An internal utility of List coercing indexes to nodes.
addRangeChangeListener(listener, token?, beforeChange?): Adds a listener for when values are added or removed at any position.
removeRangeChangeListener(listener, token?, beforeChange?): Unregisters a range change listener provided by addRangeChangeListener.
dispatchRangeChange(plus, minus, index, beforeChange?): Informs range change listeners that values were removed then added at an index.
addBeforeRangeChangeListener(listener, token?): Adds a listener for before values are added or removed at any position.
removeBeforeRangeChangeListener(listener, token?): Unregisters a range change listener provided by addBeforeRangeChangeListener or addRangeChangeListener with the beforeChange flag.
dispatchBeforeRangeChange(plus, minus, index): Informs range change listeners that values will be removed then added at an index.
addOwnPropertyChangeListener(key, listener, beforeChange?): Adds a listener for an owned property with the given name.
addBeforeOwnPropertyChangeListener(name, listener): Adds a listener for before a property changes.
removeOwnPropertyChangeListener(name, listener, beforeChange?): Unregisters a property change listener provided by addOwnPropertyChangeListener.
removeBeforeOwnPropertyChangeListener(key, listener): Unregisters a property change listener provided by addBeforeOwnPropertyChangeListener or addOwnPropertyChangeListener with the beforeChange flag.
dispatchOwnPropertyChange(key, value, beforeChange?): Informs property change listeners that the value for a property name has changed.
dispatchBeforeOwnPropertyChange(key, value): Informs property change listeners that the value for a property name will change.
makePropertyObservable(name): May perform internal changes necessary to dispatch property changes for a particular name.
makeObservable(): Makes changes observable for this collection.

Usage

var List = require("collections/list");

List()
List(values)

Example

var list = new List([1, 2, 3]);
list.splice(1, 1, 6, 5);
list.toArray();

Source code

Generated from list.md