SIMD.js has been taken out of active development in TC39 and removed from Stage 3. It is not being pursued by web browsers for implementation anymore. SIMD operations exposed to the web are under active development within WebAssembly, with operations based on the SIMD.js operations.

The static SIMD.%type%.replaceLane() method returns a new SIMD data type with the given lane value replaced.


SIMD.Float32x4.replaceLane(t, index, value)
SIMD.Float64x2.replaceLane(t, index, value)

SIMD.Int8x16.replaceLane(t, index, value)
SIMD.Int16x8.replaceLane(t, index, value)
SIMD.Int32x4.replaceLane(t, index, value)

SIMD.Uint8x16.replaceLane(t, index, value)
SIMD.Uint16x8.replaceLane(t, index, value)
SIMD.Uint32x4.replaceLane(t, index, value)

SIMD.Bool8x16.replaceLane(t, index, value)
SIMD.Bool16x8.replaceLane(t, index, value)
SIMD.Bool32x4.replaceLane(t, index, value)
SIMD.Bool64x2.replaceLane(t, index, value)


An instance of a corresponding SIMD type.
An index number for which lane to replace.
A new value to be used for the lane.

Return value

A new SIMD data type with the given lane value replaced.


  • A TypeError, if t is not the corresponding SIMD type.
  • A RangeError, if the lane index is out of bounds.


var t = SIMD.Float32x4(1, 2, 3, 4);
SIMD.Float32x4.replaceLane(t, 2, 42); 
// Float32x4[1, 2, 42, 4]


Specification Status Comment
The definition of 'SIMDConstructor.replaceLane' in that specification.
Obsolete Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support No support Nightly build No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support Nightly build No support No support No support

See also

Document Tags and Contributors

 Contributors to this page: fscholz
 Last updated by: fscholz,