🪄 magic-esquery

Type level ESQuery selector parser and matcher!

✨ Try it out in the TypeScript Playground

Installation

npm i magic-esquery

Usage

Currently the library exports only Query, Match and Parse types.

• Parse - parse selector into Selector AST

import type { Parse } from 'magic-esquery'

type res = Parse<'CallExpression'>
//   ^? type res = { type: "identifier"; value: "CallExpression" }

• Match - infer the AST Node type based on Selector AST

import type { TSESTree } from '@typescript-eslint/typescript-estree'
import type { Match } from 'magic-esquery'

type res = Match<{ type: 'identifier'; value: 'CallExpression' }, TSESTree.Node>
//   ^? type res = TSESTree.CallExpression

• Query - parse selector and infer AST Node type (basically Parse + Match)

import type { TSESTree } from '@typescript-eslint/typescript-estree'
import type { Query } from 'magic-esquery'

type res = Query<'CallExpression', TSESTree.Node>
//   ^? type res = TSESTree.CallExpression

Features

This package is tested on selectors used in @typescript-eslint/eslint-plugin, @stylistic/eslint-plugin, eslint-plugin-jest.

Check out the current ecosystem test suites here.

You can also check out additional tests for matcher and parser.

Highlights

• All ESQuery grammars are supported except :first-child, :last-child, :nth-child and :nth-last-child. They're not widely used. But if anyone wants magic-esquery to support them, issues/prs are welcome!
• Enhanced child type inference (CallExpression > .callee)
• Any combination of :matches and :not should work correctly, regardless of nesting combinations

License

MIT