108 lines
1.9 KiB
JavaScript
108 lines
1.9 KiB
JavaScript
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/*!
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* uid-safe
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* Copyright(c) 2014 Jonathan Ong
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* Copyright(c) 2015-2017 Douglas Christopher Wilson
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* MIT Licensed
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*/
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'use strict'
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/**
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* Module dependencies.
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* @private
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*/
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var randomBytes = require('random-bytes')
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/**
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* Module variables.
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* @private
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*/
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var EQUAL_END_REGEXP = /=+$/
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var PLUS_GLOBAL_REGEXP = /\+/g
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var SLASH_GLOBAL_REGEXP = /\//g
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/**
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* Module exports.
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* @public
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*/
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module.exports = uid
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module.exports.sync = uidSync
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/**
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* Create a unique ID.
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*
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* @param {number} length
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* @param {function} [callback]
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* @return {Promise}
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* @public
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*/
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function uid (length, callback) {
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// validate callback is a function, if provided
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if (callback !== undefined && typeof callback !== 'function') {
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throw new TypeError('argument callback must be a function')
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}
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// require the callback without promises
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if (!callback && !global.Promise) {
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throw new TypeError('argument callback is required')
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}
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if (callback) {
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// classic callback style
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return generateUid(length, callback)
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}
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return new Promise(function executor (resolve, reject) {
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generateUid(length, function onUid (err, str) {
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if (err) return reject(err)
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resolve(str)
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})
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})
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}
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/**
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* Create a unique ID sync.
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*
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* @param {number} length
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* @return {string}
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* @public
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*/
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function uidSync (length) {
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return toString(randomBytes.sync(length))
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}
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/**
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* Generate a unique ID string.
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*
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* @param {number} length
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* @param {function} callback
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* @private
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*/
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function generateUid (length, callback) {
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randomBytes(length, function (err, buf) {
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if (err) return callback(err)
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callback(null, toString(buf))
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})
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}
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/**
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* Change a Buffer into a string.
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*
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* @param {Buffer} buf
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* @return {string}
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* @private
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*/
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function toString (buf) {
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return buf.toString('base64')
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.replace(EQUAL_END_REGEXP, '')
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.replace(PLUS_GLOBAL_REGEXP, '-')
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.replace(SLASH_GLOBAL_REGEXP, '_')
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}
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