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