Created
December 19, 2016 16:37
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UUIDs ES6
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/** | |
* Convert a number or array of integers to a string of padded hex octets. | |
*/ | |
function asHex(value: Array<number> | Uint8Array): string { | |
return Array.from(value).map(i => ('00' + i.toString(16)).slice(-2)).join(''); | |
} | |
/** | |
* Attempt to securely generate random bytes/ | |
*/ | |
function getRandomBytes(size: number): Array<number> | Uint8Array { | |
// SPRNG | |
if ((typeof Uint8Array == 'function') && window.crypto) { | |
let buffer = new Uint8Array(size); | |
return window.crypto.getRandomValues(buffer); | |
} | |
// Insecure random | |
return Array.from(new Array(size), () => Math.random() * 255 | 0); | |
} | |
/** | |
* Generate a RFC4122-compliant v4 UUID. | |
* | |
* @see http://www.ietf.org/rfc/rfc4122.txt | |
*/ | |
export function generateUuid(): string { | |
const version = 0b01000000; | |
const clockSeqHiAndReserved = getRandomBytes(1); | |
const timeHiAndVersion = getRandomBytes(2); | |
clockSeqHiAndReserved[0] &= 0b00111111 | 0b10000000; | |
timeHiAndVersion[0] &= 0b00001111 | version; | |
return [ | |
asHex(getRandomBytes(4)), // time-low | |
'-', | |
asHex(getRandomBytes(2)), // time-mid | |
'-', | |
asHex(timeHiAndVersion), // time-high-and-version | |
'-', | |
asHex(clockSeqHiAndReserved), // clock-seq-and-reserved | |
asHex(getRandomBytes(1)), // clock-seq-loq | |
'-', | |
asHex(getRandomBytes(6)) // node | |
].join(''); | |
} |
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