@swc/types

What is @swc/types?

The @swc/types package provides TypeScript type definitions for the AST (Abstract Syntax Tree) nodes used by SWC, a super-fast compiler written in Rust. It is primarily used by developers working on tooling for JavaScript and TypeScript, such as linters, formatters, and compilers. By offering a structured way to represent code, it enables programmatic analysis, manipulation, and generation of JavaScript and TypeScript code.

What are @swc/types's main functionalities?

Defining AST Nodes

This code sample demonstrates how to define a simple AST node for a variable declaration in JavaScript using the types provided by @swc/types. It represents a variable `x` being declared and initialized with the value `10`.

{
  "type": "VariableDeclaration",
  "kind": "var",
  "declarations": [
    {
      "type": "VariableDeclarator",
      "id": {
        "type": "Identifier",
        "name": "x"
      },
      "init": {
        "type": "Literal",
        "value": 10,
        "raw": "10"
      }
    }
  ]
}

Manipulating AST Nodes

This function takes an AST node and, if it is a numeric literal, doubles its value. It showcases how @swc/types can be used to manipulate AST nodes programmatically.

function updateLiteralValue(node) {
  if (node.type === 'Literal' && typeof node.value === 'number') {
    node.value *= 2;
  }
  return node;
}

Other packages similar to @swc/types

@babel/types

Similar to @swc/types, @babel/types provides definitions and constructors for AST nodes for use with Babel. While both packages serve a similar purpose in providing tools for AST manipulation, @babel/types is tailored for the Babel ecosystem, which might make it more suitable for projects already using Babel for transpilation.

typescript

The TypeScript package itself includes utilities for working with TypeScript ASTs. While @swc/types is focused on SWC's AST format, the TypeScript package is essential for projects that need to work directly with TypeScript codebases, offering more comprehensive support for TypeScript-specific features.

README

@swc/types

Typings for @swc/core APIs. This is a separate package because SWC is used by various tools but not all of them want to depend on @swc/core. This package is very cheap, so feel free to depend on this.