Float64Array

The Float64Array typed array represents an array of 64-bit floating point numbers (corresponding to the C double data type) in the platform byte order. If control over byte order is needed, use DataView instead. The contents are initialized to 0. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).

Syntax

new Float64Array(length);
new Float64Array(typedArray);
new Float64Array(object);
new Float64Array(buffer [, byteOffset [, length]]);

For more information about the constructor syntax and the parameters, see TypedArray.

Properties

Float64Array.BYTES_PER_ELEMENT

Returns a number value of the element size. 8 in the case of an Float64Array.

Float64Array.length

Static length property whose value is 0. For the actual length (number of elements), see Float64Array.prototype.length.

Float64Array.name

Returns the string value of the constructor name. In the case of the Float64Array type: "Float64Array".

Float64Array.prototype

Prototype for the TypedArray objects.

Methods

Float64Array.from()

Creates a new Float64Array from an array-like or iterable object. See also Array.from().

Float64Array.of()

Creates a new Float64Array with a variable number of arguments. See also Array.of().

Float64Array prototype

All Float64Array objects inherit from %TypedArray%.prototype.

Properties

Float64Array.prototype.constructor

Returns the function that created an instance's prototype. This is the Float64Array constructor by default.

Float64Array.prototype.buffer Read only

Returns the ArrayBuffer referenced by the Float64Array Fixed at construction time and thus read only.

Float64Array.prototype.byteLength Read only

Returns the length (in bytes) of the Float64Array from the start of its ArrayBuffer. Fixed at construction time and thus read only.

Float64Array.prototype.byteOffset Read only

Returns the offset (in bytes) of the Float64Array from the start of its ArrayBuffer. Fixed at construction time and thus read only.

Float64Array.prototype.length Read only

Returns the number of elements hold in the Float64Array. Fixed at construction time and thus read only.

Methods

Float64Array.prototype.copyWithin()

Copies a sequence of array elements within the array. See also Array.prototype.copyWithin().

Float64Array.prototype.entries()

Returns a new Array Iterator object that contains the key/value pairs for each index in the array. See also Array.prototype.entries().

Float64Array.prototype.every()

Tests whether all elements in the array pass the test provided by a function. See also Array.prototype.every().

Float64Array.prototype.fill()

Fills all the elements of an array from a start index to an end index with a static value. See also Array.prototype.fill().

Float64Array.prototype.filter()

Creates a new array with all of the elements of this array for which the provided filtering function returns true. See also Array.prototype.filter().

Float64Array.prototype.find()

Returns the found value in the array, if an element in the array satisfies the provided testing function or undefined if not found. See also Array.prototype.find().

Float64Array.prototype.findIndex()

Returns the found index in the array, if an element in the array satisfies the provided testing function or -1 if not found. See also Array.prototype.findIndex().

Float64Array.prototype.forEach()

Calls a function for each element in the array. See also Array.prototype.forEach().

Float64Array.prototype.includes()

Determines whether a typed array includes a certain element, returning true or false as appropriate. See also Array.prototype.includes().

Float64Array.prototype.indexOf()

Returns the first (least) index of an element within the array equal to the specified value, or -1 if none is found. See also Array.prototype.indexOf().

Float64Array.prototype.join()

Joins all elements of an array into a string. See also Array.prototype.join().

Float64Array.prototype.keys()

Returns a new Array Iterator that contains the keys for each index in the array. See also Array.prototype.keys().

Float64Array.prototype.lastIndexOf()

Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found. See also Array.prototype.lastIndexOf().

Float64Array.prototype.map()

Creates a new array with the results of calling a provided function on every element in this array. See also Array.prototype.map().

Float64Array.prototype.move() Unimplemented

Former non-standard version of Float64Array.prototype.copyWithin().

Float64Array.prototype.reduce()

Apply a function against an accumulator and each value of the array (from left-to-right) as to reduce it to a single value. See also Array.prototype.reduce().

Float64Array.prototype.reduceRight()

Apply a function against an accumulator and each value of the array (from right-to-left) as to reduce it to a single value. See also Array.prototype.reduceRight().

Float64Array.prototype.reverse()

Reverses the order of the elements of an array — the first becomes the last, and the last becomes the first. See also Array.prototype.reverse().

Float64Array.prototype.set()

Stores multiple values in the typed array, reading input values from a specified array.

Float64Array.prototype.slice()

Extracts a section of an array and returns a new array. See also Array.prototype.slice().

Float64Array.prototype.some()

Returns true if at least one element in this array satisfies the provided testing function. See also Array.prototype.some().

Float64Array.prototype.sort()

Sorts the elements of an array in place and returns the array. See also Array.prototype.sort().

Float64Array.prototype.subarray()

Returns a new Float64Array from the given start and end element index.

Float64Array.prototype.values()

Returns a new Array Iterator object that contains the values for each index in the array. See also Array.prototype.values().

Float64Array.prototype.toLocaleString()

Returns a localized string representing the array and its elements. See also Array.prototype.toLocaleString().

Float64Array.prototype.toString()

Returns a string representing the array and its elements. See also Array.prototype.toString().

Float64Array.prototype[@@iterator]()

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

Examples

Different ways to create a Float64Array:

// From a length
var float64 = new Float64Array(2);
float64[0] = 42;
console.log(float64[0]); // 42
console.log(float64.length); // 2
console.log(float64.BYTES_PER_ELEMENT); // 8

// From an array
var arr = new Float64Array([21,31]);
console.log(arr[1]); // 31

// From another TypedArray
var x = new Float64Array([21, 31]);
var y = new Float64Array(x);
console.log(y[0]); // 21

// From an ArrayBuffer
var buffer = new ArrayBuffer(32);
var z = new Float64Array(buffer, 0, 4);

// From an iterable 
var iterable = function*(){ yield* [1,2,3]; }();
var float64 = new Float64Array(iterable);
// Float64Array[1, 2, 3]

Specifications

Specification	Status	Comment
Typed Array Specification	Obsolete	Superseded by ECMAScript 2015.
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'TypedArray constructors' in that specification.	Standard	Initial definition in an ECMA standard. Specified that new is required.
ECMAScript 2017 Draft (ECMA-262) The definition of 'TypedArray constructors' in that specification.	Draft

Browser compatibility

Compatibility notes

Starting with ECMAScript 2015, Float64Array constructors require to be constructed with a new operator. Calling a Float64Array constructor as a function without new, will throw a TypeError from now on.

var dv = Float64Array([1, 2, 3]);
// TypeError: calling a builtin Float64Array constructor
// without new is forbidden

var dv = new Float64Array([1, 2, 3]);

See also

• JavaScript typed arrays
• ArrayBuffer
• DataView