reregexp

  

Parse a regular expression to rule parts, and build a string match it. You can use it to mock a string with the given regular expression. it strictly abide by the real RegExp rules of the javascript language.Special cases

reregexp 主要用来解析正则表达式，根据正则表达式生成一个相匹配的随机字符串。

How to use

npm install --save reregexp

const RegexpParser = require('reregexp').default;
const r1 = new RegexpParser(/([a-z0-9]{3})_\1/);
r1.build();
// will ouput random string like this: 'a2z_a2z', '13d_13d'
const r2 = new RegexpParser(/(?<named>\w{1,2})_\1_\k<named>/);
r2.build();
// will output random string like this: 'b5_b5_b5', '9_9_9'
const r3 = new RegexpParser('/(a)\\1(?<named>b)\\k<named>(?<override>\\w+)/', {
  namedGroupConf: {
    override: ['cc', 'dd'],
  },
});
r3.build();
// will output random string "aabbcc" or "aabbdd"
const r4 = new RegexpParser(/[^\w\W]+/);
r4.build();
// will throw error, because the [^\w\W] will match nothing.
const r5 = new RegexpParser(/[^a-zA-Z0-9_\W]/);
r5.build();
// will throw error, this is the same as [^\w\W]
const r6 = new RegexpParser(/[a-z]{3}/i);
r6.build();
// will output random string like this: 'bZD' 'Poe'
RegexpParser.maxRepeat = 10;
const r7 = new RegexpParser(/a*/); // 'a' will repeated at most 10 times.
// will output: 'aaaaa'
const r8 = new RegexpParser(/a*/, {
  maxRepeat: 20, // 'a' will repeated at most 20 times
});
// extractSetAverage
const r9 = new RegexpParser(/[\Wa-z]/, {
  extractSetAverage: true, // \W will extract as all the characters match \W, a-z now doesn't have the same chance as \W 
});

Supported flags

• i ignore case, /[a-z]/i is same as /[a-zA-Z]/

• u unicode flag

• s dot all flag

the flags g m y will ignore.

API

.build()

build a string that match the regexp.

.info()

get a regexp parsed queues, flags, lastRule after remove named captures.

{
  rule: '',
  context: '',
  flags: [],
  lastRule: '',
  queues: [],
}

Build precautions,do not use any regexp anchors.

1. ^ $ the start,end anchors will be ignored.
2. (?=) (?!) (?<=) (?<!) the regexp lookhead,lookbehind will throw an error when run build().
3. \b \B will be ignored.

Special cases

1. /\1(o)/ the capture group \1 will match null, the build() will just output o, and /^\1(o)$/.test('o') === true

2. /(o)\1\2/ the capture group \2 will treated as code point of unicode. so the build() will output oo\u0002. /^(o)\1\2$/.test('oo\u0002') === true

3. /(o\1)/ the capture group \1 will match null, build() will output o, /^(o\1)$/.test('o') === true

4. /[]/ empty character class, the build() method will throw an error, because no character will match it.

5. /[^]/ negative empty character class, the build() method will output any character.

6. /[^\w\W]/ for the negative charsets, if all the characters are eliminated, the build() will throw an error. the same such as /[^a-zA-Z0-9_\W]/、/[^\s\S]/...

Questions & Bugs?

Welcome to report to us with issue if you meet any question or bug. Issue

License

MIT License.