Readonly[unscopables]Is an object whose properties have the value 'true' when they will be absent when used in a 'with' statement.
Optionalfind?: booleanOptionalfindIndex?: booleanOptionalfill?: booleanOptionalcopyWithin?: booleanOptional[iterator]?: booleanOptionalentries?: booleanOptionalkeys?: booleanOptionalvalues?: booleanOptional Readonly[unscopables]?: booleanIs an object whose properties have the value 'true' when they will be absent when used in a 'with' statement.
Optionalincludes?: booleanOptionalflatMap?: booleanOptionalflat?: booleanOptionalat?: booleanOptionalfindLast?: booleanOptionalfindLastIndex?: booleanOptionaltoReversed?: booleanOptionaltoSorted?: booleanOptionaltoSpliced?: booleanOptionalwith?: booleanOptionallength?: booleanGets or sets the length of the array. This is a number one higher than the highest index in the array.
OptionaltoString?: booleanOptionaltoLocaleString?: booleanOptionalpop?: booleanOptionalpush?: booleanOptionalconcat?: booleanOptionaljoin?: booleanOptionalreverse?: booleanOptionalshift?: booleanOptionalslice?: booleanOptionalsort?: booleanOptionalsplice?: booleanOptionalunshift?: booleanOptionalindexOf?: booleanOptionallastIndexOf?: booleanOptionalevery?: booleanOptionalsome?: booleanOptionalforEach?: booleanOptionalmap?: booleanOptionalfilter?: booleanOptionalreduce?: booleanOptionalreduceRight?: booleanGets or sets the length of the array. This is a number one higher than the highest index in the array.
Static[species]ensure that built-in class methods create a primitive Array, instead of an instance of this List class.
it is extremely important that we set the [Symbol.species] static property to Array,
otherwise any Array method that creates another Array (such as map and splice) will create an instance of List instead of an Array.
this will eventually become a huge hindrance in future computationally heavy subclasses of this class that utilize the splice often.
related reading material:
Symbol.species static property: mdn link.Symbol.species instead of symbol_species from "alias.ts": see the comment inside the body of [Symbol.iterator].Protected Readonlyrcthe reference counting Map, that bookkeeps the multiplicity of each item in the list.
Readonlygetget the reference count (multiplicity) of a specific item in the list.
note that the reference count for a non-existing item is undefined instead of 0.
Protected Readonlysetset the reference count of a specific item in the list.
Protected Readonlydeldelete the reference counting of a specific item in the list. a true is returned if the item did exist in rc, prior to deletion.
StaticofReturns the value of the first element in the array where predicate is true, and undefined otherwise.
find calls predicate once for each element of the array, in ascending order, until it finds one where predicate returns true. If such an element is found, find immediately returns that element value. Otherwise, find returns undefined.
OptionalthisArg: anyIf provided, it will be used as the this value for each invocation of predicate. If it is not provided, undefined is used instead.
Returns the index of the first element in the array where predicate is true, and -1 otherwise.
find calls predicate once for each element of the array, in ascending order, until it finds one where predicate returns true. If such an element is found, findIndex immediately returns that element index. Otherwise, findIndex returns -1.
OptionalthisArg: anyIf provided, it will be used as the this value for each invocation of predicate. If it is not provided, undefined is used instead.
Changes all array elements from start to end index to a static value and returns the modified array
value to fill array section with
Optionalstart: numberindex to start filling the array at. If start is negative, it is treated as length+start where length is the length of the array.
Optionalend: numberindex to stop filling the array at. If end is negative, it is treated as length+end.
Returns the this object after copying a section of the array identified by start and end to the same array starting at position target
If target is negative, it is treated as length+target where length is the length of the array.
If start is negative, it is treated as length+start. If end is negative, it is treated as length+end.
Optionalend: numberIf not specified, length of the this object is used as its default value.
Iterator
Returns an iterable of key, value pairs for every entry in the array
Returns an iterable of keys in the array
Returns an iterable of values in the array
Determines whether an array includes a certain element, returning true or false as appropriate.
The element to search for.
OptionalfromIndex: numberThe position in this array at which to begin searching for searchElement.
Calls a defined callback function on each element of an array. Then, flattens the result into a new array. This is identical to a map followed by flat with depth 1.
A function that accepts up to three arguments. The flatMap method calls the callback function one time for each element in the array.
OptionalthisArg: ThisAn object to which the this keyword can refer in the callback function. If thisArg is omitted, undefined is used as the this value.
Returns the item located at the specified index.
The zero-based index of the desired code unit. A negative index will count back from the last item.
Returns the value of the last element in the array where predicate is true, and undefined otherwise.
findLast calls predicate once for each element of the array, in descending order, until it finds one where predicate returns true. If such an element is found, findLast immediately returns that element value. Otherwise, findLast returns undefined.
OptionalthisArg: anyIf provided, it will be used as the this value for each invocation of predicate. If it is not provided, undefined is used instead.
Returns the index of the last element in the array where predicate is true, and -1 otherwise.
findLastIndex calls predicate once for each element of the array, in descending order, until it finds one where predicate returns true. If such an element is found, findLastIndex immediately returns that element index. Otherwise, findLastIndex returns -1.
OptionalthisArg: anyIf provided, it will be used as the this value for each invocation of predicate. If it is not provided, undefined is used instead.
Returns a copy of an array with its elements reversed.
Returns a copy of an array with its elements sorted.
OptionalcompareFn: (a: T, b: T) => numberFunction used to determine the order of the elements. It is expected to return a negative value if the first argument is less than the second argument, zero if they're equal, and a positive value otherwise. If omitted, the elements are sorted in ascending, ASCII character order.
[11, 2, 22, 1].toSorted((a, b) => a - b) // [1, 2, 11, 22]
Copies an array and removes elements and, if necessary, inserts new elements in their place. Returns the copied array.
The zero-based location in the array from which to start removing elements.
The number of elements to remove.
Elements to insert into the copied array in place of the deleted elements.
The copied array.
Copies an array and removes elements while returning the remaining elements.
The zero-based location in the array from which to start removing elements.
OptionaldeleteCount: numberThe number of elements to remove.
A copy of the original array with the remaining elements.
Copies an array, then overwrites the value at the provided index with the given value. If the index is negative, then it replaces from the end of the array.
The index of the value to overwrite. If the index is negative, then it replaces from the end of the array.
The value to write into the copied array.
The copied array with the updated value.
Returns a string representation of an array.
Returns a string representation of an array. The elements are converted to string using their toLocaleString methods.
Optionaloptions: NumberFormatOptions & DateTimeFormatOptionsAdds all the elements of an array into a string, separated by the specified separator string.
Optionalseparator: stringA string used to separate one element of the array from the next in the resulting string. If omitted, the array elements are separated with a comma.
Reverses the elements in an array in place. This method mutates the array and returns a reference to the same array.
Returns a copy of a section of an array. For both start and end, a negative index can be used to indicate an offset from the end of the array. For example, -2 refers to the second to last element of the array.
Optionalstart: numberThe beginning index of the specified portion of the array. If start is undefined, then the slice begins at index 0.
Optionalend: numberThe end index of the specified portion of the array. This is exclusive of the element at the index 'end'. If end is undefined, then the slice extends to the end of the array.
Sorts an array in place. This method mutates the array and returns a reference to the same array.
OptionalcompareFn: (a: T, b: T) => numberFunction used to determine the order of the elements. It is expected to return a negative value if the first argument is less than the second argument, zero if they're equal, and a positive value otherwise. If omitted, the elements are sorted in ascending, ASCII character order.
[11,2,22,1].sort((a, b) => a - b)
Returns the index of the first occurrence of a value in an array, or -1 if it is not present.
The value to locate in the array.
OptionalfromIndex: numberThe array index at which to begin the search. If fromIndex is omitted, the search starts at index 0.
Returns the index of the last occurrence of a specified value in an array, or -1 if it is not present.
The value to locate in the array.
OptionalfromIndex: numberThe array index at which to begin searching backward. If fromIndex is omitted, the search starts at the last index in the array.
Determines whether all the members of an array satisfy the specified test.
A function that accepts up to three arguments. The every method calls the predicate function for each element in the array until the predicate returns a value which is coercible to the Boolean value false, or until the end of the array.
OptionalthisArg: anyAn object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.
Determines whether all the members of an array satisfy the specified test.
A function that accepts up to three arguments. The every method calls the predicate function for each element in the array until the predicate returns a value which is coercible to the Boolean value false, or until the end of the array.
OptionalthisArg: anyAn object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.
Determines whether the specified callback function returns true for any element of an array.
A function that accepts up to three arguments. The some method calls the predicate function for each element in the array until the predicate returns a value which is coercible to the Boolean value true, or until the end of the array.
OptionalthisArg: anyAn object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.
Performs the specified action for each element in an array.
A function that accepts up to three arguments. forEach calls the callbackfn function one time for each element in the array.
OptionalthisArg: anyAn object to which the this keyword can refer in the callbackfn function. If thisArg is omitted, undefined is used as the this value.
Calls a defined callback function on each element of an array, and returns an array that contains the results.
A function that accepts up to three arguments. The map method calls the callbackfn function one time for each element in the array.
OptionalthisArg: anyAn object to which the this keyword can refer in the callbackfn function. If thisArg is omitted, undefined is used as the this value.
Returns the elements of an array that meet the condition specified in a callback function.
A function that accepts up to three arguments. The filter method calls the predicate function one time for each element in the array.
OptionalthisArg: anyAn object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.
Returns the elements of an array that meet the condition specified in a callback function.
A function that accepts up to three arguments. The filter method calls the predicate function one time for each element in the array.
OptionalthisArg: anyAn object to which the this keyword can refer in the predicate function. If thisArg is omitted, undefined is used as the this value.
Calls the specified callback function for all the elements in an array. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
Calls the specified callback function for all the elements in an array. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
A function that accepts up to four arguments. The reduce method calls the callbackfn function one time for each element in the array.
If initialValue is specified, it is used as the initial value to start the accumulation. The first call to the callbackfn function provides this value as an argument instead of an array value.
Calls the specified callback function for all the elements in an array, in descending order. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
Calls the specified callback function for all the elements in an array, in descending order. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
A function that accepts up to four arguments. The reduceRight method calls the callbackfn function one time for each element in the array.
If initialValue is specified, it is used as the initial value to start the accumulation. The first call to the callbackfn function provides this value as an argument instead of an array value.
StaticisStaticfromCreates an array from an async iterator or iterable object.
inserts an item at the specified index, shifting all items ahead of it one position to the front.
negative indices are also supported for indicating the position of the newly added item after the array's length has incremented.
import { assertEquals } from "jsr:@std/assert"
const arr = new List([0, 1, 2, 3, 4])
arr.insert(-1, 5) // similar to pushing
assertEquals([...arr], [0, 1, 2, 3, 4, 5])
arr.insert(-2, 4.5)
assertEquals([...arr], [0, 1, 2, 3, 4, 4.5, 5])
arr.insert(1, 0.5)
assertEquals([...arr], [0, 0.5, 1, 2, 3, 4, 4.5, 5])
deletes an item at the specified index, shifting all items ahead of it one position to the back.
negative indices are also supported for indicating the deletion index from the end of the array.
import { assertEquals } from "jsr:@std/assert"
const arr = new List([0, 0.5, 1, 2, 3, 4, 4.5, 5])
arr.delete(-1) // similar to popping
assertEquals([...arr], [0, 0.5, 1, 2, 3, 4, 4.5])
arr.delete(-2)
assertEquals([...arr], [0, 0.5, 1, 2, 3, 4.5])
arr.delete(1)
assertEquals([...arr], [0, 1, 2, 3, 4.5])
get an item at the specified index.
this is equivalent to using index-based getter: my_list[index].
Protectedonthis overridable method gets called when a new unique item is determined to be added to the list.
this method is called before the item is actually added to the array, but it is executed right after its reference counter has incremented to 1.
avoid accessing or mutating the array itself in this method's body (consider it an undefined behavior).
the item that is being added.
Protectedonthis overridable method gets called when a unique item (reference count of 1) is determined to be removed from the list.
this method is called before the item is actually removed from the array, but it is executed right after its reference counter has been deleted.
avoid accessing or mutating the array itself in this method's body (consider it an undefined behavior).
the item that is being removed.
Protectedincincrements the reference count of each item in the provided array of items.
the items whose counts are to be incremented.
Protecteddecdecrements the reference count of each item in the provided array of items.
the items whose counts are to be decremented.
Appends new elements to the end of an array, and returns the new length of the array.
New elements to add to the array.
Removes the last element from an array and returns it. If the array is empty, undefined is returned and the array is not modified.
Removes the first element from an array and returns it. If the array is empty, undefined is returned and the array is not modified.
Inserts new elements at the start of an array, and returns the new length of the array.
Elements to insert at the start of the array.
Removes elements from an array and, if necessary, inserts new elements in their place, returning the deleted elements.
The zero-based location in the array from which to start removing elements.
OptionaldeleteCount: numberThe number of elements to remove.
An array containing the elements that were deleted.
swap the position of two items by their index.
if any of the two indices is out of bound, then appropriate number of empty elements will be created to fill the gap;
similar to how index-based assignment works (i.e. my_list[off_bound_index] = "something" will increase my_list's length).
import { assertEquals } from "jsr:@std/assert"
const arr = new List<string>(["0", "4", "2", "3", "1", "5", "6"])
arr.swap(1, 4)
assertEquals(arr.slice(), ["0", "1", "2", "3", "4", "5", "6"])
// swapping elements with an out of bound index will create additional intermediate `empty` elements.
// moreover, the existing element that is swapped will have `undefined` put in its place instead of `empty`.
assertEquals(arr.length, 7)
arr.swap(5, 9)
assertEquals(arr.length, 10)
assertEquals(arr.slice(), ["0", "1", "2", "3", "4", undefined, "6", , , "5"]) // notice the empty entries.
sets the value at the specified index, updating the counter accordingly.
always use this method instead of index-based assignment, because the latter is not interceptable (except when using proxies):
my_list[index] = "hello"my_list.set(index, "hello")Staticfrom
a specialized list that keeps track of the number of duplicates of each item in the list, similar to a reference counter.
this class automatically updates the reference counter on any mutations to the list at
O(log(n)), wherenis the number of unique items.note that you must use the set method for index-based assignment, otherwise the class will not be able track the changes made.
my_list[index] = "hello"my_list.set(index, "hello")Example