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56 lines
1.5 KiB
JavaScript

// imported from https://github.com/unshiftio/yeast
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.yeast = exports.decode = exports.encode = void 0;
const alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_".split(""), length = 64, map = {};
let seed = 0, i = 0, prev;
/**
* Return a string representing the specified number.
*
* @param {Number} num The number to convert.
* @returns {String} The string representation of the number.
* @api public
*/
function encode(num) {
let encoded = "";
do {
encoded = alphabet[num % length] + encoded;
num = Math.floor(num / length);
} while (num > 0);
return encoded;
}
exports.encode = encode;
/**
* Return the integer value specified by the given string.
*
* @param {String} str The string to convert.
* @returns {Number} The integer value represented by the string.
* @api public
*/
function decode(str) {
let decoded = 0;
for (i = 0; i < str.length; i++) {
decoded = decoded * length + map[str.charAt(i)];
}
return decoded;
}
exports.decode = decode;
/**
* Yeast: A tiny growing id generator.
*
* @returns {String} A unique id.
* @api public
*/
function yeast() {
const now = encode(+new Date());
if (now !== prev)
return (seed = 0), (prev = now);
return now + "." + encode(seed++);
}
exports.yeast = yeast;
//
// Map each character to its index.
//
for (; i < length; i++)
map[alphabet[i]] = i;