| // Unique ID creation requires a high quality random # generator. In the |
| // browser this is a little complicated due to unknown quality of Math.random() |
| // and inconsistent support for the `crypto` API. We do the best we can via |
| // feature-detection |
| |
| // getRandomValues needs to be invoked in a context where "this" is a Crypto |
| // implementation. Also, find the complete implementation of crypto on IE11. |
| var getRandomValues = (typeof(crypto) != 'undefined' && crypto.getRandomValues && crypto.getRandomValues.bind(crypto)) || |
| (typeof(msCrypto) != 'undefined' && typeof window.msCrypto.getRandomValues == 'function' && msCrypto.getRandomValues.bind(msCrypto)); |
| |
| if (getRandomValues) { |
| // WHATWG crypto RNG - http://wiki.whatwg.org/wiki/Crypto |
| var rnds8 = new Uint8Array(16); // eslint-disable-line no-undef |
| |
| module.exports = function whatwgRNG() { |
| getRandomValues(rnds8); |
| return rnds8; |
| }; |
| } else { |
| // Math.random()-based (RNG) |
| // |
| // If all else fails, use Math.random(). It's fast, but is of unspecified |
| // quality. |
| var rnds = new Array(16); |
| |
| module.exports = function mathRNG() { |
| for (var i = 0, r; i < 16; i++) { |
| if ((i & 0x03) === 0) r = Math.random() * 0x100000000; |
| rnds[i] = r >>> ((i & 0x03) << 3) & 0xff; |
| } |
| |
| return rnds; |
| }; |
| } |