Float64Array

Summary

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

Float64Array(length);
Float64Array(typedArray);
Float64Array(object);
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

Length property whose value is 3.

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()

See Array.from(). Not implemented, see bug 896608.

Float64Array.of()

See Array.of(). Not implemented, see bug 896608.

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()

See Array.prototype.copyWithin().

Float64Array.prototype.move() Unimplemented

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

Float64Array.prototype.set()

Stores multiple values in the Float64Array, reading input values from a specified array.

Float64Array.prototype.subarray()

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

Examples

// 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 = Float64Array(buffer, 0, 4);

Specifications

Browser compatibility

See also

• JavaScript typed arrays
• ArrayBuffer
• DataView