woodpile: SWC AST visitor in Javascript

[kwonoj]

https://www.npmjs.com/package/woodpile

Woodpile is a utility library to traverse SWC ASTs in Javascript. It is a thin interop layer to the SWC's rust implementation of its visitor macro, attempt to provide consistent, synchronized mechanism to traverse ASTs in Javascript as well. This package could be useful to duck typing, prototyping SWC plugin in Javascript as its interface aims to provide similar experience as SWC's visitor macro.

For those reason, this package aims correctness over performance. There are inevitable costs to exchange data between Javascript to Rust, and vice versa. If you want to achieve peak performace, you should use SWC's visitor macro directly.

This is a userland alternative to handwritten JS visitor in @swc/core for the easier ast traversing.

Usage

visit is a main interface to traverse AST.

Currently, visit accepts an object with visit property have corresponding callbacks to traverse.

const { visit } = require('woodpile');
const { parseSync } = require('@swc/core');

const ast = parseSync('console.log("Hello, World!")');

visit(ast, {
    visit: {
        // Callbacks with visit${NodeName} will be called recursively for the node
        visitProgram: (node, self) => {
            console.log('visitProgram', node);
        },
        visitExpr: (node) => {
            console.log('visitExpr', node);
        }
    },
});

[kwonoj]

Just to be clear, this is nothing related to writing-plugin-in-javascript.