Shared memory and atomics for ECMAscript
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This is a specification for Shared Memory and Atomics for ECMAScript, a proposal submitted to Ecma TC39 and currently at Stage 3 in the ECMAScript approval process.

Documentation and other materials


Firefox, Chrome and WebKit ship with prototype implementations of the proposal; these are largely compatible.

  • The feature is enabled by default in Firefox Nightly; starting with Firefox 46, users of Developer Edition, Aurora, Beta, and Release can visit about:config and set the option javascript.options.shared_memory to true.
  • The feature is off by default in Chrome, but can be enabled by passing the command line options --js-flags=--harmony-sharedarraybuffer and --enable-blink-feature=SharedArrayBuffer. (Known to work in Chrome 48.)
  • The feature is enabled by default in WebKit Nightly and Safari Technology Preview as of STP 20.


The sources for the specs are in the tc39/ subdirectory and the formatted versions are generated with the script.