test-examples.mjs

import glob from "glob";
import fs from "fs";
import child_process from "child_process";
import path from "path";
import { URL } from 'url';

const pathname = new URL('.', import.meta.url).pathname;
const __dirname = process.platform !== 'win32' ? pathname : pathname.substring(1)

let tempFileName = path.join(__dirname, '..', '_tempFile.res')
let tempFileNameRegex = /_tempFile\.res/g

// TODO: In the future we need to use the appropriate rescript version for each doc version variant
//       see the package.json on how to define another rescript version
let compilersDir = path.join(__dirname, "..", "compilers")

let bsc = path.join(compilersDir, 'node_modules', 'rescript-1110', process.platform, 'bsc.exe');
let rescriptBin = path.join(compilersDir, 'node_modules', 'rescript-1110', 'rescript');
let rescriptCoreCompiled = path.join(compilersDir, 'node_modules', '@rescript', 'core', 'lib', 'ocaml');
let rescriptReactCompiled = path.join(compilersDir, 'node_modules', '@rescript', 'react', 'lib', 'ocaml');

const prepareCompilers = () => {
  if (fs.existsSync(bsc)) {
    return;
  }
  console.log("compilers not installed. Installing compilers...");
  child_process.execFileSync("npm", ['install'], {cwd: compilersDir})
}

const prepareDependencies = () => {
  if (fs.existsSync(rescriptCoreCompiled) && fs.existsSync(rescriptReactCompiled)) {
    return;
  }
  console.log("Dependencies not installed. Installing...");
  child_process.execFileSync(rescriptBin, [], {cwd: compilersDir})
}

let parseFile = content => {
  if (!/```res (example|prelude|sig)/.test(content)) {
    return
  }

  let inCodeBlock = false
  let moduleId = 0
  return content.split('\n').map(line => {
    let modifiedLine = ''
    if (line.startsWith('```res example')) {
      inCodeBlock = true
      modifiedLine = `/* _MODULE_EXAMPLE_START */ module M_${moduleId++} = {`
    } else if (line.startsWith('```res prelude')) {
      inCodeBlock = true
      modifiedLine = `/* _MODULE_PRELUDE_START */ include {`
    } else if (line.startsWith('```res sig')) {
      inCodeBlock = true
      modifiedLine = `/* _MODULE_SIG_START */ module type M_${moduleId++} = {`
    } else if (inCodeBlock) {
      if (line.startsWith('```')) {
        inCodeBlock = false
        modifiedLine = '} // _MODULE_END'
      } else {
        modifiedLine = line
      }
    }

    return modifiedLine
  }).join('\n')
}

let postprocessOutput = (file, error) => {
  return error.stderr.toString()
    .replace(tempFileNameRegex, path.relative('.', file))
    .replace(/\/\* _MODULE_(EXAMPLE|PRELUDE|SIG)_START \*\/.+/g, (_, capture) => {
      return '```res ' + (capture === 'EXAMPLE' ? 'example' : capture === 'PRELUDE' ? 'prelude' : 'sig')
    })
    .replace(/(.*)\}(.*)\/\/ _MODULE_END/g, (_, cap1, cap2) => {
      // cap1 cap2 might be empty or ansi coloring code
      return cap1 + '```' + cap2
    })
}


prepareCompilers();
prepareDependencies();

console.log("Running tests...")
fs.writeFileSync(tempFileName, '')

let success = true

glob.sync(__dirname + '/../pages/docs/{manual/latest,react/latest}/**/*.mdx').forEach((file) => {
  let content = fs.readFileSync(file, {encoding: 'utf-8'})
  let parsedResult = parseFile(content)
  if (parsedResult != null) {
    fs.writeFileSync(tempFileName, parsedResult)
    try {
      // -109 for suppressing `Toplevel expression is expected to have unit type.`
      // Most doc snippets do e.g. `Belt.Array.length(["test"])`, which triggers this
      child_process.execFileSync(
        bsc,
        [
          tempFileName,
          '-I',
          rescriptCoreCompiled,
          '-I',
          rescriptReactCompiled,
          '-bs-jsx',
          '4',
          '-w',
          '-109',
          '-uncurried',
          '-open',
          'RescriptCore',
        ],
        { stdio: "pipe" }
      );
    } catch (e) {
      process.stdout.write(postprocessOutput(file, e))
      success = false
    }
  }
})

fs.unlinkSync(tempFileName)
process.exit(success ? 0 : 1)