index.js•1.93 kB
/*!
* uid-safe
* Copyright(c) 2014 Jonathan Ong
* Copyright(c) 2015-2017 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module dependencies.
* @private
*/
var randomBytes = require('random-bytes')
/**
* Module variables.
* @private
*/
var EQUAL_END_REGEXP = /=+$/
var PLUS_GLOBAL_REGEXP = /\+/g
var SLASH_GLOBAL_REGEXP = /\//g
/**
* Module exports.
* @public
*/
module.exports = uid
module.exports.sync = uidSync
/**
* Create a unique ID.
*
* @param {number} length
* @param {function} [callback]
* @return {Promise}
* @public
*/
function uid (length, callback) {
// validate callback is a function, if provided
if (callback !== undefined && typeof callback !== 'function') {
throw new TypeError('argument callback must be a function')
}
// require the callback without promises
if (!callback && !global.Promise) {
throw new TypeError('argument callback is required')
}
if (callback) {
// classic callback style
return generateUid(length, callback)
}
return new Promise(function executor (resolve, reject) {
generateUid(length, function onUid (err, str) {
if (err) return reject(err)
resolve(str)
})
})
}
/**
* Create a unique ID sync.
*
* @param {number} length
* @return {string}
* @public
*/
function uidSync (length) {
return toString(randomBytes.sync(length))
}
/**
* Generate a unique ID string.
*
* @param {number} length
* @param {function} callback
* @private
*/
function generateUid (length, callback) {
randomBytes(length, function (err, buf) {
if (err) return callback(err)
callback(null, toString(buf))
})
}
/**
* Change a Buffer into a string.
*
* @param {Buffer} buf
* @return {string}
* @private
*/
function toString (buf) {
return buf.toString('base64')
.replace(EQUAL_END_REGEXP, '')
.replace(PLUS_GLOBAL_REGEXP, '-')
.replace(SLASH_GLOBAL_REGEXP, '_')
}