34 lines
969 B
JavaScript
34 lines
969 B
JavaScript
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// Unique ID creation requires a high quality random # generator. In the
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// browser this is a little complicated due to unknown quality of Math.random()
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// and inconsistent support for the `crypto` API. We do the best we can via
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// feature-detection
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var rng;
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var crypto = global.crypto || global.msCrypto; // for IE 11
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if (crypto && crypto.getRandomValues) {
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// WHATWG crypto RNG - http://wiki.whatwg.org/wiki/Crypto
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var rnds8 = new Uint8Array(16); // eslint-disable-line no-undef
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rng = function whatwgRNG() {
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crypto.getRandomValues(rnds8);
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return rnds8;
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};
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}
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if (!rng) {
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// Math.random()-based (RNG)
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//
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// If all else fails, use Math.random(). It's fast, but is of unspecified
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// quality.
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var rnds = new Array(16);
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rng = function() {
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for (var i = 0, r; i < 16; i++) {
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if ((i & 0x03) === 0) r = Math.random() * 0x100000000;
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rnds[i] = r >>> ((i & 0x03) << 3) & 0xff;
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}
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return rnds;
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};
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}
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module.exports = rng;
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