# Array

### length <sub>number</sub>

### at(index) <sub>function</sub>

Return the item at index 'index', supporting negative indices to count from
the end. If 'index' is out of range, returns undefined.



**index**: The index of the element to return (can be negative).


**Returns**: The element at the given index, or undefined.


### with(index, value) <sub>function</sub>

Return a shallow copy of the array, but with the element at 'index' replaced
by 'value'. If 'index' is negative, it counts from the end. Throws if out of range.



**index**: The zero-based index (can be negative) to replace.

**value**: The new value for the specified position.


**Returns**: A new array with the updated element.


### concat(items) <sub>function</sub>

Return a new array that is the result of concatenating this array with
any additional arrays or values provided.



**items**: One or more arrays or values to concatenate.


**Returns**: A new array with the items appended.


### every(callback, thisArg) <sub>function</sub>

Return true if the provided callback function returns a truthy value for
every element in the array; otherwise false.



**callback**: A function(element, index, array) => boolean.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: True if all elements pass the test, otherwise false.


### some(callback, thisArg) <sub>function</sub>

Return true if the provided callback function returns a truthy value for at
least one element in the array; otherwise false.



**callback**: A function(element, index, array) => boolean.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: True if at least one element passes the test, otherwise false.


### forEach(callback, thisArg) <sub>function</sub>

Call the provided callback function once for each element in the array.
Does not produce a return value.



**callback**: A function(element, index, array).

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: None


### map(callback, thisArg) <sub>function</sub>

Create a new array with the results of calling a provided callback function
on every element in this array.



**callback**: A function(element, index, array) => newElement.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: A new array of transformed elements.


### filter(callback, thisArg) <sub>function</sub>

Create a new array containing all elements for which the provided callback
function returns a truthy value.



**callback**: A function(element, index, array) => boolean.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: A new array of elements that passed the test.


### reduce(callback, initialValue) <sub>function</sub>

Apply a callback function against an accumulator and each element in the
array (from left to right) to reduce it to a single value.



**callback**: A function(accumulator, element, index, array) => newAccumulator.

**initialValue**: Optional. The initial value for the accumulator.


**Returns**: The single resulting value.


### reduceRight(callback, initialValue) <sub>function</sub>

Similar to reduce(), except it processes elements from right to left.



**callback**: A function(accumulator, element, index, array) => newAccumulator.

**initialValue**: Optional. The initial value for the accumulator.


**Returns**: The single resulting value.


### fill(value, start, end) <sub>function</sub>

Fill the array with a static value from 'start' index up to (but not including)
'end' index. Modifies the original array.



**value**: The value to fill.

**start**: The starting index (default 0).

**end**: The ending index (default array.length).


**Returns**: The modified array (with filled values).


### find(callback, thisArg) <sub>function</sub>

Return the first element in the array that satisfies the provided callback
function. If none is found, return undefined.



**callback**: A function(element, index, array) => boolean.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: The first matching element, or undefined if not found.


### findIndex(callback, thisArg) <sub>function</sub>

Return the index of the first element in the array that satisfies the
provided callback function. If none is found, return -1.



**callback**: A function(element, index, array) => boolean.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: The index of the first matching element, or -1 if not found.


### findLast(callback, thisArg) <sub>function</sub>

Return the last element in the array that satisfies the provided callback
function, searching from right to left. If none is found, return undefined.



**callback**: A function(element, index, array) => boolean.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: The last matching element, or undefined if not found.


### findLastIndex(callback, thisArg) <sub>function</sub>

Return the index of the last element in the array that satisfies the
provided callback function, searching from right to left. If none is found,
return -1.



**callback**: A function(element, index, array) => boolean.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: The index of the last matching element, or -1 if not found.


### indexOf(searchElement, fromIndex) <sub>function</sub>

Return the first index at which a given element can be found. If not present,
return -1.



**searchElement**: The item to locate in the array.

**fromIndex**: The index at which to start searching (default 0).


**Returns**: The index of the found element, or -1 if not found.


### lastIndexOf(searchElement, fromIndex) <sub>function</sub>

Return the last index at which a given element can be found, or -1 if not
present. Searches backward from 'fromIndex'.



**searchElement**: The item to locate in the array.

**fromIndex**: The index at which to start searching backward (default array.length - 1).


**Returns**: The last index of the found element, or -1 if not found.


### includes(searchElement, fromIndex) <sub>function</sub>

Return a boolean indicating whether the array contains the given element,
comparing elements using the SameValueZero algorithm.



**searchElement**: The value to search for.

**fromIndex**: The position in the array to start searching (default 0).


**Returns**: True if the element is found, otherwise false.


### join(separator) <sub>function</sub>

Join all elements of the array into a string, separated by 'separator'.



**separator**: The delimiter string to separate elements (default ',').


**Returns**: A string of array elements joined by the separator.


### toString() <sub>function</sub>

Return a string representing the elements of the array, separated by commas.
Overrides Object.prototype.toString.



**Returns**: A comma-separated string of array elements.


### toLocaleString() <sub>function</sub>

Return a localized string representing the array and its elements, calling
each element's toLocaleString if available.



**Returns**: A locale-sensitive, comma-separated string of array elements.


### pop() <sub>function</sub>

Remove the last element from the array and return it. This changes the length
of the array.



**Returns**: The removed element, or undefined if the array is empty.


### push(items) <sub>function</sub>

Append one or more elements to the end of the array and return the new length
of the array.



**items**: One or more items to append.


**Returns**: The new length of the array.


### shift() <sub>function</sub>

Remove the first element from the array and return it. This changes the length
of the array.



**Returns**: The removed element, or undefined if the array is empty.


### unshift(items) <sub>function</sub>

Insert one or more elements at the start of the array and return the new
length of the array.



**items**: One or more elements to insert at the start.


**Returns**: The new length of the array.


### reverse() <sub>function</sub>

Reverse the elements of the array in place and return the modified array.



**Returns**: The reversed array.


### toReversed() <sub>function</sub>

Return a shallow copy of the array in reverse order, without modifying the original array.



**Returns**: A new reversed array.


### sort(compareFunction) <sub>function</sub>

Sort the array in place, returning it. By default, sorts elements as strings in ascending order. An optional compareFunction may be used for custom sorting.



**compareFunction**: A function(a, b) => number, defining sort order.


**Returns**: The sorted array.


### toSorted(compareFunction) <sub>function</sub>

Return a shallow copy of the array, sorted according to the optional compare
function, without modifying the original array.



**compareFunction**: A function(a, b) => number, defining sort order.


**Returns**: A new sorted array.


### slice(start, end) <sub>function</sub>

Return a shallow copy of a portion of the array into a new array object, selected from 'start' to 'end' (end not included).



**start**: The beginning index (0-based). Negative values count from the end.

**end**: The end index (exclusive). Negative values count from the end.


**Returns**: A new array containing the extracted elements.


### splice(start, deleteCount, items) <sub>function</sub>

Change the contents of the array by removing or replacing existing elements and/or adding new elements in place. Returns an array of removed elements.



**start**: The index at which to start changing the array.

**deleteCount**: Number of elements to remove.

**items**: Elements to add in place of the removed elements.


**Returns**: An array containing the removed elements (if any).


### toSpliced(start, deleteCount, items) <sub>function</sub>

Return a shallow copy of the array, with a splice-like operation applied at 'start' removing 'deleteCount' elements and adding 'items'. Does not mutate the original array.



**start**: The index at which to start the splice operation.

**deleteCount**: Number of elements to remove.

**items**: Elements to add in place of the removed elements.


**Returns**: A new array with the splice applied.


### copyWithin(target, start, end) <sub>function</sub>

Copy a sequence of array elements within the array, overwriting existing values. This operation is performed in place and returns the modified array.



**target**: The index at which to copy the sequence to.

**start**: The beginning index of the sequence to copy.

**end**: The end index (exclusive) of the sequence to copy (default array.length).


**Returns**: The modified array.


### flatMap(callback, thisArg) <sub>function</sub>

Return a new array formed by applying a callback function to each element and then flattening the result by one level.



**callback**: A function(element, index, array) => array or value.

**thisArg**: Optional. A value to use as 'this' within the callback.


**Returns**: A new array with the flattened results.


### flat(depth) <sub>function</sub>

Return a new array with all sub-array elements concatenated into it recursively up to the specified depth.



**depth**: The maximum depth to flatten (default 1).


**Returns**: A new flattened array.


### values() <sub>function</sub>

Return a new Array Iterator object that contains the values for each index in the array.



**Returns**: An iterator over the array's elements.


### keys() <sub>function</sub>

Return a new Array Iterator object that contains the keys (indexes) for each index in the array.



**Returns**: An iterator over the array's indices.


### entries() <sub>function</sub>

Return a new Array Iterator object that contains key/value pairs for each index in the array. Each entry is [index, value].



**Returns**: An iterator over [index, value] pairs.


### add(other) <sub>function</sub>

Non-standard. Add corresponding elements of the current array and 'other' element-wise, returning a new array. Behavior depends on data types.



**other**: Another array or scalar to add to each element.


**Returns**: A new array with element-wise sum results.


### sub(other) <sub>function</sub>

Non-standard. Subtract corresponding elements of 'other' from the current array element-wise, returning a new array. Behavior depends on data types.



**other**: Another array or scalar to subtract from each element.


**Returns**: A new array with element-wise difference results.


### div(other) <sub>function</sub>

Non-standard. Divide each element of the current array by the corresponding element of 'other' (or a scalar) element-wise, returning a new array. Behavior depends on data types.



**other**: Another array or scalar for the division.


**Returns**: A new array with element-wise division results.


### scale() <sub>function</sub>

### lerp() <sub>function</sub>

### x <sub>accessor</sub>

### y <sub>accessor</sub>

### xy <sub>accessor</sub>

### r <sub>accessor</sub>

### g <sub>accessor</sub>

### b <sub>accessor</sub>

### a <sub>accessor</sub>

### rgb <sub>accessor</sub>

### rgba <sub>accessor</sub>

### filter!(fn) <sub>function</sub>

Perform an in-place filter of this array using the provided callback 'fn'.
Any element for which 'fn' returns a falsy value is removed. The array is modified
and then returned.



**fn**: A callback function(element, index, array) => boolean.


**Returns**: The filtered (modified) array.


### delete(item) <sub>function</sub>

Remove the first occurrence of 'item' from the array, if it exists.
Returns undefined.



**item**: The item to remove.


**Returns**: undefined


### copy() <sub>function</sub>

Return a deep copy of this array by applying 'deep_copy' to each element.
The resulting array is entirely new.



**Returns**: A new array that is a deep copy of the original.


### equal(b) <sub>function</sub>

Check if this array and array 'b' have the same elements in the same order.
If they are of different lengths, return false. Otherwise compare them via JSON.



**b**: Another array to compare against.


**Returns**: True if they match, false otherwise.


### last() <sub>function</sub>

Return the last element of this array. If the array is empty, returns undefined.



**Returns**: The last element of the array, or undefined if empty.


### wrapped(x) <sub>function</sub>

Return a copy of the array with the first 'x' elements appended to the end.
Does not modify the original array.



**x**: The number of leading elements to re-append.


**Returns**: A new array with the leading elements wrapped to the end.


### wrap_idx(x) <sub>function</sub>

Wrap the integer 'x' around this array's length, ensuring the resulting index
lies within [0, this.length - 1].



**x**: The index to wrap.


**Returns**: A wrapped index within this array's bounds.


### mirrored(x) <sub>function</sub>

Return a new array that appends a reversed copy (excluding the last element)
of itself to the end. For example, [1,2,3] -> [1,2,3,2,1]. If the array has length
<= 1, a copy of it is returned directly.



**Returns**: A new "mirrored" array.