buuh/packages/migrate/test/transform.test.js

import { test } from 'node:test'
import assert from 'node:assert'

import transform from '../lib/transform.js'

test('converts a classic choo v7 header to v8 ESM', () => {
  const src = [
    "var choo = require('choo')",
    "var html = require('choo/html')",
    "var devtools = require('choo-devtools')",
    '',
    'var app = choo()',
    "app.use(devtools())",
    'module.exports = app'
  ].join('\n')

  const { code, changed, notes } = transform(src)
  assert.ok(changed)
  assert.match(code, /import choo from '@uhhm\/buuh'/)
  assert.match(code, /import html from '@uhhm\/buuh-html'/)
  assert.match(code, /import devtools from '@uhhm\/buuh-devtools'/)
  assert.match(code, /export default app/)
  assert.deepStrictEqual(notes, [])
})

test('destructured and property requires', () => {
  const src = [
    "const { render } = require('some-lib')",
    "const thing = require('other-lib').thing",
    "const dflt = require('third-lib').default",
    "require('./side-effect')"
  ].join('\n')

  const { code } = transform(src)
  assert.match(code, /import { render } from 'some-lib'/)
  assert.match(code, /import { thing as thing } from 'other-lib'/)
  assert.match(code, /import dflt from 'third-lib'/)
  assert.match(code, /import '\.\/side-effect'/)
})

test('already-ESM sources get specifiers remapped', () => {
  const src = [
    "import choo from 'choo'",
    "import html from 'nanohtml'",
    "import raw from 'nanohtml/raw'",
    "import morph from 'nanomorph'",
    "import Component from 'nanocomponent'"
  ].join('\n')

  const { code } = transform(src)
  assert.match(code, /from '@uhhm\/buuh'/)
  assert.match(code, /from '@uhhm\/buuh-html'\n/)
  assert.match(code, /from '@uhhm\/buuh-html\/raw'/)
  assert.match(code, /from '@uhhm\/buuh-html\/morph'/)
  assert.match(code, /from '@uhhm\/buuh-component'/)
})

test('retired packages produce notes, not rewrites', () => {
  const src = [
    "var nanobus = require('nanobus')",
    "var lazyRoute = require('choo-lazy-route')"
  ].join('\n')

  const { code, notes } = transform(src)
  assert.match(code, /from 'nanobus'/, 'retired specifier left for the human')
  assert.ok(notes.some((n) => n.includes('nanobus')))
  assert.ok(notes.some((n) => n.includes('lazy()')), 'choo-lazy-route points at lazy()')
})

test('dynamic import() specifiers are remapped too', () => {
  const { code } = transform("const mod = await import('choo/html')")
  assert.match(code, /import\('@uhhm\/buuh-html'\)/)
})

test('unconvertible CJS is reported honestly', () => {
  const src = [
    "module.exports.helper = function () {}",
    "function f () { const x = require('choo') }"
  ].join('\n')

  const { code, notes } = transform(src)
  assert.match(code, /require\('@uhhm\/buuh'\)/, 'specifier remapped even inside functions')
  assert.ok(notes.some((n) => n.includes('module.exports')))
  assert.ok(notes.some((n) => n.includes('require() calls remain')))
})

test('non-choo sources pass through untouched', () => {
  const src = "import fs from 'node:fs'\nexport const x = 1\n"
  const { changed, notes } = transform(src)
  assert.strictEqual(changed, false)
  assert.deepStrictEqual(notes, [])
})