multimath/lib/wa_detect.js

Core to create fast image math in WebAssembly and JS.

// Detect WebAssembly support.
// - Check global WebAssembly object
// - Try to load simple module (can be disabled via CSP)
//
'use strict';


var wa;


module.exports = function hasWebAssembly() {
  // use cache if called before;
  if (typeof wa !== 'undefined') return wa;

  wa = false;

  if (typeof WebAssembly === 'undefined') return wa;

  // If WebAssenbly is disabled, code can throw on compile
  try {
    // https://github.com/brion/min-wasm-fail/blob/master/min-wasm-fail.in.js
    // Additional check that WA internals are correct

    /* eslint-disable comma-spacing, max-len */
    var bin      = new Uint8Array([ 0,97,115,109,1,0,0,0,1,6,1,96,1,127,1,127,3,2,1,0,5,3,1,0,1,7,8,1,4,116,101,115,116,0,0,10,16,1,14,0,32,0,65,1,54,2,0,32,0,40,2,0,11 ]);
    var module   = new WebAssembly.Module(bin);
    var instance = new WebAssembly.Instance(module, {});

    // test storing to and loading from a non-zero location via a parameter.
    // Safari on iOS 11.2.5 returns 0 unexpectedly at non-zero locations
    if (instance.exports.test(4) !== 0) wa = true;

    return wa;
  } catch (__) {}

  return wa;
};