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stringify.js
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stringify.js
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import validate from './validate.js';
/**
* Convert array of 16 byte values to UUID string format of the form:
* XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
*/
const byteToHex = [];
for (let i = 0; i < 256; ++i) {
byteToHex.push((i + 0x100).toString(16).substr(1));
}
function stringify(arr, offset = 0) {
// Note: Be careful editing this code! It's been tuned for performance
// and works in ways you may not expect. See https://github.com/uuidjs/uuid/pull/434
const uuid = (
byteToHex[arr[offset + 0]] +
byteToHex[arr[offset + 1]] +
byteToHex[arr[offset + 2]] +
byteToHex[arr[offset + 3]] +
'-' +
byteToHex[arr[offset + 4]] +
byteToHex[arr[offset + 5]] +
'-' +
byteToHex[arr[offset + 6]] +
byteToHex[arr[offset + 7]] +
'-' +
byteToHex[arr[offset + 8]] +
byteToHex[arr[offset + 9]] +
'-' +
byteToHex[arr[offset + 10]] +
byteToHex[arr[offset + 11]] +
byteToHex[arr[offset + 12]] +
byteToHex[arr[offset + 13]] +
byteToHex[arr[offset + 14]] +
byteToHex[arr[offset + 15]]
).toLowerCase();
// Consistency check for valid UUID. If this throws, it's likely due to one
// of the following:
// - One or more input array values don't map to a hex octet (leading to
// "undefined" in the uuid)
// - Invalid input values for the RFC `version` or `variant` fields
if (!validate(uuid)) {
throw TypeError('Stringified UUID is invalid');
}
return uuid;
}
export default stringify;