randexp will generate a random string that matches a given RegExp Javascript object.
var RandExp = require('randexp');
// supports grouping and piping
new RandExp(/hello+ (world|to you)/).gen();
// => hellooooooooooooooooooo world
// sets and ranges and references
new RandExp(/<([a-z]\w{0,20})>foo<\1>/).gen();
// => <m5xhdg>foo<m5xhdg>
// wildcard
new RandExp(/random stuff: .+/).gen();
// => random stuff: 湐箻ໜ䫴㳸長���邓蕲뤀쑡篷皇硬剈궦佔칗븛뀃匫鴔事좍ﯣ⭼ꝏ䭍詳蒂䥂뽭
// ignore case
new RandExp(/xxx xtreme dragon warrior xxx/i).gen();
// => xxx xtReME dRAGON warRiOR xXX
// dynamic regexp shortcut
new RandExp('(sun|mon|tue|wednes|thurs|fri|satur)day', 'i');
// is the same as
new RandExp(new RegExp('(sun|mon|tue|wednes|thurs|fri|satur)day', 'i'));If you're only going to use gen() once with a regexp and want slightly shorter syntax for it
var randexp = require('randexp').randexp;
randexp(/[1-6]/); // 4
randexp('great|good( job)?|excellent'); // greatIf you miss the old syntax
require('randexp').sugar();
/yes|no|maybe|i don't know/.gen(); // maybeRegular expressions are used in every language, every programmer is familiar with them. Regex can be used to easily express complex strings. What better way to generate a random string than with a tool you can easily use to express the string any way you want?
Thanks to String-Random for giving me the idea to make this in the first place and randexp for the sweet .gen() syntax.
Sets like the . character will match anything except a new line. In this case, a character with a random char code between 0 and 65535 will be generated. If you want to overwrite this function you can change the anyRandChar function in the randexp object.
var randexp = new RandExp(/./);
randexp.anyRandChar = function() {
return 'c';
};If using RandExp.sugar()
var regexp = /./;
regexp.anyRandChar = function() {
return 'c';
};Repetitional tokens such as *, +, and {3,} have an infinite max range. In this case, randexp looks at its min and adds 100 to it to get a useable max value. If you want to use another int other than 100 you can change the max property in the randexp object.
var randexp = new RandExp(/no{1,}/);
randexp.max = 1000000;With RandExp.sugar()
var regexp = /(hi)*/;
regexp.max = 1000000;There are some regular expressions which can never match any string.
-
Ones with badly placed positionals such as
/a^/and/$c/m. Randexp will ignore positional tokens. -
Back references to non-existing groups like
/(a)\1\2/. Randexp will ignore those references, returning an empty string for them. If the group exists only after the reference is used such as in/\1 (hey)/, it will too be ignored. -
Custom negated character sets with two sets inside that cancel each other out. Example:
/[^\w\W]/. If you give this to randexp, it will ignore both set tokens.
Other cancelling out character sets like /[^\D]/ are bad too. These are the same as /[\d]/. Except it will be slow in generating a matching string because it will first generate a random character and then check if it's in the set inside. It will take a while to randomly generate an integer out of 65535 characters.
npm install randexp
Download the minified version from the latest release.
Tests are written with mocha
npm testMIT