files/en-us/web/javascript/reference/global_objects/float64array/index.md
The Float64Array typed array represents an array of 64-bit floating point numbers in the platform byte order. If control over byte order is needed, use {{jsxref("DataView")}} instead. The contents are initialized to 0 unless initialization data is explicitly provided. 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).
Float64Array is a subclass of the hidden {{jsxref("TypedArray")}} class.
Float64Array object.Also inherits static properties from its parent {{jsxref("TypedArray")}}.
8 in the case of Float64Array.Inherits static methods from its parent {{jsxref("TypedArray")}}.
Also inherits instance properties from its parent {{jsxref("TypedArray")}}.
These properties are defined on Float64Array.prototype and shared by all Float64Array instances.
8 in the case of a Float64Array.Float64Array instances, the initial value is the {{jsxref("Float64Array/Float64Array", "Float64Array")}} constructor.Inherits instance methods from its parent {{jsxref("TypedArray")}}.
// From a length
const 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
const x = new Float64Array([21, 31]);
console.log(x[1]); // 31
// From another TypedArray
const y = new Float64Array(x);
console.log(y[0]); // 21
// From an ArrayBuffer
const buffer = new ArrayBuffer(64);
const z = new Float64Array(buffer, 8, 4);
console.log(z.byteOffset); // 8
// From an iterable
const iterable = (function* () {
yield* [1, 2, 3];
})();
const float64FromIterable = new Float64Array(iterable);
console.log(float64FromIterable);
// Float64Array [1, 2, 3]
{{Specifications}}
{{Compat}}
Float64Array in core-js