pino-esbuild.js

const { dirname, sep, join, resolve } = require('path')
const { build } = require('esbuild')
const { readFile } = require('fs/promises')

// TODO: Check how to solve when [dir] or [hash] are used
function pinoPlugin(options) {
  options = { transports: [], ...options }

  return {
    name: 'pino',
    setup(currentBuild) {
      const pino = dirname(require.resolve('pino'))
      const threadStream = dirname(require.resolve('thread-stream'))

      // Adjust entrypoints if it is an array
      let entrypoints = currentBuild.initialOptions.entryPoints
      if (Array.isArray(entrypoints)) {
        let outbase = currentBuild.initialOptions.outbase

        // Find the outbase
        if (!outbase) {
          const hierarchy = entrypoints[0].split(sep)

          let i = 0
          outbase = ''
          let nextOutbase = ''
          do {
            outbase = nextOutbase
            i++
            nextOutbase = hierarchy.slice(0, i).join(sep)
          } while (entrypoints.every(e => e.startsWith(`${nextOutbase}/`)))
        }

        const newEntrypoints = {}
        for (const entrypoint of entrypoints) {
          const destination = (outbase ? entrypoint.replace(`${outbase}/`, '') : entrypoint).replace(/.js$/, '')
          newEntrypoints[destination] = entrypoint
        }

        entrypoints = newEntrypoints
      }

      // Now add our endpoints
      const userEntrypoints = Object.entries(entrypoints)
      const customEntrypoints = {
        'thread-stream-worker': join(threadStream, 'lib/worker.js'),
        'pino-worker': join(pino, 'lib/worker.js'),
        'pino-pipeline-worker': join(pino, 'lib/worker-pipeline.js'),
        'pino-file': join(pino, 'file.js')
      }
      // TODO: Add files in options.transport as well using require.resolve
      currentBuild.initialOptions.entryPoints = { ...entrypoints, ...customEntrypoints }

      // // Add a loader for all entrypoints to add the banner
      currentBuild.onResolve({ filter: /\.js$/ }, args => {
        if (args.kind === 'entry-point') {
          const absolutePath = resolve(process.cwd(), args.path)

          // Find in the entrypoints the one which has this definition in order to get the folder
          const destination = userEntrypoints.find(pair => resolve(process.cwd(), pair[1]) === absolutePath)

          if (destination) {
            return { path: join(args.resolveDir, args.path), pluginData: { pinoBundlerOverride: destination[0] } }
          }
        }

        return undefined
      })

      // Prepend our overrides
      const banner = `/* Start of pino-webpack-bundler additions */
      function pinoWebpackBundlerAbsolutePath(p) {
        try {
          return require('path').join(__dirname, p)
        } catch(e) {
          // This is needed not to trigger a warning if we try to use within CJS - Do we have another way?
          const f = new Function('p', 'return new URL(p, import.meta.url).pathname');
          return f(p)
        }
      }      
      `

      currentBuild.onLoad({ filter: /\.js$/ }, async args => {
        if (!args.pluginData || !args.pluginData.pinoBundlerOverride) {
          return undefined
        }

        const contents = await readFile(args.path, 'utf8')

        // Find how much the asset is nested
        const prefix =
          args.pluginData.pinoBundlerOverride
            .split(sep)
            .slice(0, -1)
            .map(() => '..')
            .join(sep) || '.'

        const declarations = Object.keys(customEntrypoints)
          .map(
            id =>
              `'${id === 'pino-file' ? 'pino/file' : id}': pinoWebpackBundlerAbsolutePath('${prefix}${sep}${id}.js')`
          )
          .join(',')

        const overrides = `\nglobalThis.pinoBundlerOverrides = {${declarations}};\n/* End of pino-webpack-bundler additions */\n\n`

        return {
          contents: banner + overrides + contents
        }
      })
    }
  }
}

build({
  entryPoints: {
    main: 'src/index.js',
  },
  bundle: true,
  platform: 'node',
  outdir: 'dist',
  plugins: [pinoPlugin({ transport: 'pino-pretty' })]
}).catch(() => process.exit(1))

@davipon

You're welcome, your feedback made my day!
Thanks for the plugin, I will take a look soon.
Also, definitely create the PR, so we can list it.

CC: @mcollina