ecma-262-regexp-parser v0.9.0

ECMA-262 regexp parser

Regexp Parser, implemented according to EMCA-262 Specification. Implemented all syntax constructions from es2022.

Requirements

• Typescript >= 4.9
• Node.js >= 16

Install

$ npm i ecma-262-regexp-parser --save

$ yarn global add ecma-262-regexp-parser

$ pnpm install --global ecma-262-regexp-parser

API Reference

parseRegexp(source: string | RegExp): RegexpNode

Returns AST of full regexp expression (e.g. /Hello!/gm). Throws, if got any syntax error.

import { parseRegexp } from 'ecma-262-regexp-parser';

const regexpNode = parseRegexp(/[A-z]*/gm);

parseRegexpNode(source: string): AnyRegexpNode

Returns AST of any regexp expression (e.g. (Hello|Hi)!). Throws, if got any syntax error.

import { parseRegexpNode } from 'ecma-262-regexp-parser';

const regexpNode = parseRegexpNode('(?:Maybe)\\snot');

printRegexpNode(node: AnyRegexpNode): string

Prints AST back to string as full representation (e.g. '/hello/gi')

import { printRegexpNode } from 'ecma-262-regexp-parser';

const regexp = parseRegexpNode(someAST);

createRegExpFromRegexpNode(node: RegexpNode): RegExp

Generates javascript RegExp from RegexpNode.

import { createRegExpFromRegexpNode, parseRegexp } from 'ecma-262-regexp-parser';

const regexpNode = parseRegexp(/a|b/);
const regexp = createRegExpFromRegexpNode(regexpNode);
console.log(regexp.test('a')) // <- true

traverseRegexpNode(node: RegexpNode, visitors: ...): void

Traverses nodes, can be used to collect information about regexp. Visitors are object, where key is node name (or * for calling on each node) and value is full visitor or shorthand:

import { traverseRegexp, parseRegexp } from 'ecma-262-regexp-parser';

const regexpNode = parseRegexp(/a|b/);
traverseRegexp(regexpNode, {
  '*': (node) => console.log(node), // will log every node enter,
  Group: {
    enter(node) {
    }, // will be called before child nodes traversing
    exit(node) {
    }, // will be called after all child nodes got traversed
  },
})

factory

Exports all node creation methods. Names are matched node names, e.g. CharNode -> factory.createCharNode.

import { factory, CharType } from 'ecma-262-regexp-parser';

const charNode = factory.createCharNode('a', CharType.Simple, { start: 0, end: 0 });

types

Exports node type checkers, that can be used to narrow node type.

import { types, parseRegexpNode } from 'ecma-262-regexp-parser';

const node = parseRegexpNode('(a|b)');
if (types.isGroupNode(node)) {
  // node type is narrowed to GroupNode
}

Enums

• SyntaxKind - describes all possible node types.
• ControlEscapeCharType - types of ControlEscapeCharNode;
• QuantifierType - types of QuantifierNode;
• CharType - types of CharNode.