Time slots app prototype
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'use strict';
// limit of Crypto.getRandomValues()
// https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues
var MAX_BYTES = 65536;
// Node supports requesting up to this number of bytes
// https://github.com/nodejs/node/blob/master/lib/internal/crypto/random.js#L48
var MAX_UINT32 = 4294967295;
var crypto = global.crypto || global.msCrypto;
if (!crypto || !crypto.getRandomValues) {
console.warn('Secure random number generation is not supported by this browser.\nUse Chrome, Firefox or Internet Explorer 11');
}
export default function randomBytes(size, cb) {
// phantomjs needs to throw
if (size > MAX_UINT32)
throw new RangeError('requested too many random bytes');
var bytes = Buffer.allocUnsafe(size);
if (size > 0) { // getRandomValues fails on IE if size == 0
if (size > MAX_BYTES) { // this is the max bytes crypto.getRandomValues
// can do at once see https://developer.mozilla.org/en-US/docs/Web/API/window.crypto.getRandomValues
for (var generated = 0; generated < size; generated += MAX_BYTES) {
// buffer.slice automatically checks if the end is past the end of
// the buffer so we don't have to here
crypto.getRandomValues(bytes.slice(generated, generated + MAX_BYTES));
}
}
else {
crypto.getRandomValues(bytes);
}
}
if (typeof cb === 'function') {
return process.nextTick(function () {
cb(null, bytes);
});
}
return bytes;
}