AST Crawler

Two small utilities for generating an AST Map (mapping of file paths to ast for their contents) and for visiting each of those entries in the AST Map.

Installation:

yarn add @matthamlin/ast-crawler

Usage:

import { generateASTMap, visit, find } from '@matthamlin/ast-crawler'

// Implementing a local cache for parsers
import { parse } from '@babel/parser'
import path from 'path'

let parsers = {}

function createParser(filepath) {
  let extension = path.extname(filepath)
  if (parsers[extension]) {
    return parsers[extension]
  }
  if (extension === '.tsx' || extension === '.ts') {
    parsers['.ts'] = parsers['.tsx'] = (contents) => {
      return parse(contents, {
        plugins: ['typescript'],
        sourceType: 'module',
      })
    }
    return parsers['.ts']
  } else {
    parsers[extension] = (contents) => {
      return parse(contents, {
        plugins: ['flow'],
        sourceType: 'module',
      })
    }
    return parsers[extension]
  }
}

let astMap = generateASTMap({
  files: find({ root: path.join('./src'), extensions: ['.js', '.ts', '.tsx'] }),
  createParser,
})

function visitor({ ast, path: filePath }) {
  // do whatever you want here with the ast and the filepath
}

visit({
  visitor,
  astMap,
})

Tools:

• Typescript
• Babel
• Jest

TODO:

• Refine AST type