regexp-coder

Building readable JavaScript/TypeScript regular expressions gracefully.

API Documentation

RegExp Coder API Documentation

Introduction

The regexp-coder is using fluent APIs (with nested parameters) to help you to build regular expressions in a readable way.

• Sample: Check IPv4

Let's see how to use the util to define a IPv4 address in decimal number. IPv4 address is presented in format of: <0-255>.<0-255>.<0-255>.<0-255>. There are two elements, one is decimal number which is from 0 to 255, and another element is .. We can define the decimal part as subIP: /\d|\d\d|[1]\d\d|2[0-4]\d|25[0-5]/ and the do element as dot: /\./

For example:

import { RegExpCoder } from 'regexp-coder';

const subIP = /(\d|\d\d|1\d\d|2[0-4]\d|25[0-5])/;
const dot = /\./;
const ipv4Exp = RegExpCoder.new()
	.join(
		subIP,
		dot,
		subIP,
		dot,
		subIP,
		dot,
		subIP,
	)
	.enableMatchWhole()
	.toRegExp();

console.log(ipv4Exp.test('192.168.0.1')); // true
console.log(ipv4Exp.test('192-168-0-1')); // false

• If you like fluent API, you can use the define-build pattern.

You can define elements sub-ip and dot as variables and use them later. For example:

import { RegExpCoder } from 'regexp-coder';

const ipv4Exp = RegExpCoder.new()
	.define('sub-ip', /(\d|\d\d|1\d\d|2[0-4]\d|25[0-5])/)
	.define('dot', /\./)
	.join(
		'sub-ip',
		'dot',
		'sub-ip',
		'dot',
		'sub-ip',
		'dot',
		'sub-ip',
	)
	.enableMatchWhole()
	.toRegExp();

console.log(ipv4Exp.test('192.168.0.1')); // true
console.log(ipv4Exp.test('192-168-0-1')); // false

• For complex variables, you use build-stash-build pattern. The stash() method will save the current result as a variable, then get the object cleared.

For example:

import { RegExpCoder } from 'regexp-coder';

const ipv4Exp = RegExpCoder.new()
	.group(
		RegExpCoder.new().or(
			/\d/,
			/\d\d/,
			/1\d\d/,
			/2[0-4]\d/,
			/25[0-5]/,
		),
	)
	.stash('sub-ip')
	.define('dot', /\./)
	.join(
		'sub-ip',
		'dot',
		'sub-ip',
		'dot',
		'sub-ip',
		'dot',
		'sub-ip',
	)
	.enableMatchWhole()
	.toRegExp();

console.log(ipv4Exp.test('192.168.0.1')); // true
console.log(ipv4Exp.test('192-168-0-1')); // false

Main classes

RegExpCoder

| Method | Description | | --------------------------- | ----------------------------------------------------------- | | static methods: | | | encodeRegExp | Encode a raw string to a regular expression string. | | | For example, it will convert . -> \. | | new() | Create an instance of RegExpCoder | | instance methods: | | | join() | Append an expression, .e.g xyz | | group() | Append a group expression, e.g. (xyz) | | or() | Append an or expression, e.g. x|y|z) | | set() | Append a set expression, e.g. [xyz] | | negatedSet() | Append a negated set expression, e.g. [^xyz] | | lookahead() | Append a lookahead expression, e.g. x(?=y) | | negatedLookahead() | Append a negated lookahead expression, e.g. x(?!y) | | lookbehind() | Append a lookbehind expression, e.g. (?<=y)x | | negatedLookbehind() | Append a negated lookbehind expression, e.g. (?<!y)x | | | | | define() | Define an expression, .e.g xyz | | defineGroup() | Define a group expression, e.g. (xyz) | | defineOr() | Define an or expression, e.g. x|y|z) | | defineSet() | Define a set expression, e.g. [xyz] | | defineNegatedSet() | Define a negated set expression, e.g. [^xyz] | | defineLookahead() | Define a lookahead expression, e.g. x(?=y) | | defineNegatedLookahead() | Define a negated lookahead expression, e.g. x(?!y) | | defineLookbehind() | Define a lookbehind expression, e.g. (?<=y)x | | defineNegatedLookbehind() | Define a negated lookbehind expression, e.g. (?<!y)x | | | | | stash() | Define an expression from the current state. | | | | | source | Get the source of the current state. | | toRegExp() | Get the RegExp instance of the current state. | | enableMatchWhole | Enable the expression to match the whole string. e.g. ^x$ | | beginGroup | Begin a group expression. e.g. ( | | endGroup | End the group expression, e.g. ')' |

RegExpOptions

For example:

import { RegExpCoder } from 'regexp-coder';

const group = true;
const ipv4Exp = RegExpCoder.new()
	.or(
		/\d/,
		/\d\d/,
		/1\d\d/,
		/2[0-4]\d/,
		/25[0-5]/,
		{ group }, // <-- Use options here
	)
	.stash('sub-ip')
	.define('dot', /\./)
	.join(
		'sub-ip',
		'dot',
		'sub-ip',
		'dot',
		'sub-ip',
		'dot',
		'sub-ip',
	)
	.enableMatchWhole()
	.toRegExp();

console.log(ipv4Exp.test('192.168.0.1')); // true
console.log(ipv4Exp.test('192-168-0-1')); // false

| Members | Description | | ------------------------ | ---------------------------------------------------------------------------------- | | qualifier | (xyz)*, Define qualifier for the current expression | | groupQualifiedItem | (xyz)*, If need to add a group before the qualifier for the current expression | | notRememberQualifiedItem | (?:xyz)*, If need not to remember the qualifier group for the current expression | | groupItem | (x)(y)(z), If need to add a group for each items of the current expression | | group | (xyz), If need to add a group for the current expression | | name | (?name:xyz)*, name for the group | | notRemember | (?:xyz), If need not to remember the group for the current expression | | or | x|y|z, If use the or operation for the items in the expression | | set | [xyz], If use the set operation for the items in the expression | | negated | [^xyz], If use the negated set operation for the items in the expression |

RegExpSpec

This is one to one members of Regular Expressions.