babel-types

What is babel-types?

The babel-types package is a part of the Babel compiler ecosystem. It provides builders, validators, and conversion utilities for the various types of nodes in the Abstract Syntax Tree (AST) used by Babel. This package is essential for manipulating the AST generated or consumed by Babel, allowing for custom transformations and analysis of JavaScript code.

What are babel-types's main functionalities?

AST Node Builders

Builders are functions that help in creating AST nodes. This example demonstrates creating a binary expression node that represents the multiplication of two identifiers, 'a' and 'b'.

const t = require('babel-types');
const binaryExpression = t.binaryExpression('*', t.identifier('a'), t.identifier('b'));

AST Node Validators

Validators are functions that check if a node is of a certain type or meets certain criteria. In this example, the validator checks if the node is an identifier with the name 'a'.

const t = require('babel-types');
const isValid = t.isIdentifier(t.identifier('a'), { name: 'a' });

Type Conversion Utilities

Conversion utilities allow for the transformation of one type of node into another. This example shows converting a numeric literal into a string literal.

const t = require('babel-types');
const numericLiteral = t.numericLiteral(5);
const asStringLiteral = t.stringLiteral(`${numericLiteral.value}`);

Other packages similar to babel-types

@babel/types

This is the newer version of babel-types, rebranded and scoped under the Babel organization. It offers the same functionalities but is more actively maintained and includes updates for the latest JavaScript features.

recast

Recast provides AST manipulation capabilities with a focus on preserving the original formatting as much as possible. While babel-types is more about creating and validating AST nodes, recast is geared towards parsing and reprinting code with minimal changes.

acorn

Acorn is a fast, small JavaScript parser that generates an AST. While it doesn't offer manipulation utilities like babel-types, it's often used in conjunction with other tools for analysis and transformation tasks.

README

babel-types