DataView.prototype.setFloat64()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The setFloat64() method of DataView instances takes a number and stores it as a 64-bit floating point number in the 8 bytes starting at the specified byte offset of this DataView. There is no alignment constraint; multi-byte values may be stored at any offset within bounds.
Try it
// Create an ArrayBuffer with a size in bytes
const buffer = new ArrayBuffer(16);
const view = new DataView(buffer);
view.setFloat64(1, Math.PI);
console.log(view.getFloat64(1));
// Expected output: 3.141592653589793
Syntax
setFloat64(byteOffset, value)
setFloat64(byteOffset, value, littleEndian)
Parameters
byteOffset-
The offset, in bytes, from the start of the view to store the data in.
value-
The value to set. For how the value is encoded in bytes, see Value encoding and normalization.
littleEndianOptional-
Indicates whether the data is stored in little- or big-endian format. If
falseorundefined, a big-endian value is written.
Return value
Exceptions
RangeError-
Thrown if the
byteOffsetis set such that it would store beyond the end of the view.
Examples
Using setFloat64()
const buffer = new ArrayBuffer(10);
const dataview = new DataView(buffer);
dataview.setFloat64(0, 3);
dataview.getFloat64(1); // 3.785766995733679e-270
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-dataview.prototype.setfloat64 |