Lib mode format: es.min

[yyx990803]

Clear and concise description of the problem

Currently when building in lib mode we do not minify the ES build because that would remove pure annotations and break treeshaking. However, this is assuming that the ES build is only used with bundlers. In the future, more users could be using ES builds over CDNs with native ES imports, so a minified ES build could be necessary for those cases.

Suggested solution

// vite config
build: {
  lib: {
    formats: ['es', 'es.min']
  }
}

Alternative

lib: { minifyES: true }

Additional context

vuejs/petite-vue#112

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[Niputi]

prior related #5167 #6314

[Kurtil]

What about #6670 ? :P

[bluwy]

In #8754, I've updated so that minifyWhitespace would only be turned off (which is removing the pure annotations). minifySyntax and minifyIdentifiers are enabled so we have partial minification for es lib build.

[Junior2Ran]

is there any progress about this topic?

[mindplay-dk]

I don't understand, is minifying just disabled entirely for es library output?

I've tried for example this:

  build: {
    lib: {
      // ...
      formats: ["es"]
    },
    minify: "terser",
    terserOptions: {
      compress: true,
      mangle: true,
    },
  }

It doesn't minify or mangle at all - I have no control of the terser options at all?

I can understand having sensible defaults, so you don't accidentally break tree shaking - but blocking me from configuring terser entirely? And not even a warning - it just doesn't work. Very confusing.

At this time, minify: "esbuild" gives a significantly smaller file, because it actually compresses and minifies - with minify: "terser" it doesn't minify at all. How is this setting useful?

I was able to manually minify with terser after the fact, so it's not that this isn't possible.

npm exec terser -- -c -m --module dist/lib.js > dist/lib.min.js

[Teaghy]

Excuse me, has this problem been solved yet?

[abarke]

Any solution?

[soerenmeier]

As a workaround you can use a small plugin to minify the file:

import esbuild from 'esbuild';

const plugin = {
	name: 'minify',
	closeBundle: () => {
		esbuild.buildSync({
			entryPoints: ['./dist/lib.js'],
			minify: true,
			allowOverwrite: true,
			outfile: './dist/lib.js'
		})
	}
};

[sinedied]

Would love to see this implemented!

Currently this is my workaround:

Add an extra esm format to lib entry (don't mind the TS error):

    lib: {
      entry: './src/index.ts',
      formats: ['es', 'esm'],
      fileName: (format) => ({
        es: `${pkg.name}.js`,
        esm: `${pkg.name}.min.js`,
      })[format]

Then add this plugin to the build:

import { transform } from 'esbuild';

function minifyEs() {
  return {
    name: 'minifyEs',
    renderChunk: {
      order: 'post',
      async handler(code, chunk, outputOptions) {
        if (outputOptions.format === 'es' && chunk.fileName.endsWith('.min.js')) {
          return await transform(code, { minify: true });
        }
        return code;
      },
    }
  };
}

This will generate the ES amd ES minified variants.

[maranomynet]

@sinedied Thanks.

I've got //@ts-check at the top of my vite.config.js and to suppress the TS error I use this:

  formats: [
    'cjs',
    // @ts-expect-error
    'esm',
    // @ts-expect-error
    'system',
  ],

(BTW: 'system' format is supported by rollup and seems to work, despite vite not documenting it as an option.)

[abarke]

Please support #6585

[YornQiu]

so stupid, there is no way to minify 'es', terserOptions' compress and mangle doesn't work at all.

[stfn00]

If it helps, I've made a custom plugin that implements terser on generateBundle phase, to minify.

import { resolve } from 'node:path'
import { defineConfig } from 'vite'
import { minify } from "terser";
import autoprefixer from 'autoprefixer'

function minifyBundles() {
  return {
    name: "minifyBundles",
    async generateBundle(options, bundle) {
      for (let key in bundle) {
        if (bundle[key].type == 'chunk' && key.endsWith('.js')) {
          const minifyCode = await minify(bundle[key].code, { sourceMap: false })
          bundle[key].code = minifyCode.code
        }
      }
      return bundle
    },
  }
}

export default defineConfig({
  appType: 'custom',
  css: {
    devSourcemap: true,
    postcss: {
      plugins: [
        autoprefixer
      ],
    }
  },
  build: {
    target: ['es2015'],
    outDir: 'dist',
    emptyOutDir: true,
    cssCodeSplit: true,
    sourcemap: false,
    lib: {
      formats: ['es'],
      entry: [
        resolve(__dirname, 'src/scripts/main.js'),
        resolve(__dirname, 'src/scripts/critical.js'),
      ],
      fileName: '[name]',
    },
  },
  plugins: [
    minifyBundles()
  ]
})

[itssumitrai]

Coming back end of 2023, this is a fairly important missing feature. For modern libraries esm is the way to go and no way to minify the output just makes it useless. Sticking to rollup for builds is the way to go atm

[daraclare]

Is there any plan to look at this does anyone know?

[Kurtil]

Is there any plan to look at this does anyone know?

No news. This is my npm run build command workaround :

vite build && esbuild my/lib/path.js --minify --outfile=my/lib/path.js --allow-overwrite

I build using vite then minify using esbuild separatly... :/

[mindplay-dk]

In the future, more users could be using ES builds over CDNs with native ES imports, so a minified ES build could be necessary for those cases.

2.5 years on, this is beginning to feel like a pressing matter.

[stefanholzapfel]

Maybe I got something wrong, but why not use the minify flag directly in the build options?

    build: {
        outDir: './dist/bundle-minified',
        target: ['es2015'],
        lib: {
            entry: 'src/index.ts',
            formats: ['es', 'amd'],
            fileName: (format) => ({
                es: `spotteron.ui.esm.min.js`,
                amd: `spotteron.ui.amd.min.js`,
            })[format]
        },
        rollupOptions: {
            output: {
                inlineDynamicImports: true
            }
        },
        sourcemap: false,
        minify: true,
        cssMinify: true
    }

I get a minified version. Is the configurability the problem?

[krasevych]

any update?

[jmlee2k]

This is yet another example of a small plugin which will minify the lib - I haven't tested it beyond my very simple use case.

benefits:

• it doesn't rely on having to repeat the dist file name(s)
• it uses esbuild for minification (which the eventual es.min solution will likely do, making it easier to move over once it's implemented)

const minifyBundle = ():Plugin=>({
	name:"minify-bundle",
	async generateBundle(_,bundle)
	{
		for (const asset of Object.values(bundle))
		{
			if (asset.type == "chunk")
				asset.code = (await esbuild.transform(asset.code,{minify:true})).code;
		}
	}
});

[Makio64]

Thanks @jmlee2k the code you provide works for me

This said : being allow to minify a lib file should be by default for a bundler ?

[WIStudent]

In my case, I need to bundle a script that is directly imported by the browser somewhere else (so no further tree-shaking). I noticed that the es build is almost twice the size of the iife build.

iife: 374.14 kB
es: 608.17 kB

vite/packages/vite/src/node/plugins/esbuild.ts

Lines 422 to 442 in cf813cc

	if (isEsLibBuild) {
	// Disable minify whitespace as it breaks tree-shaking
	return {
	...options,
	minify: false,
	minifyIdentifiers: options.minifyIdentifiers ?? true,
	minifySyntax: options.minifySyntax ?? true,
	minifyWhitespace: false,
	treeShaking: true,
	}
	} else {
	return {
	...options,
	minify: false,
	minifyIdentifiers: options.minifyIdentifiers ?? true,
	minifySyntax: options.minifySyntax ?? true,
	minifyWhitespace: options.minifyWhitespace ?? true,
	treeShaking: true,
	}
	}
	}

Wouldn't changing line 429 to minifyWhitespace: options.minifyWhitespace ?? false solve this issue? That way, anyone who wants the smallest bundle and doesn't need further tree-shaking could set

esbuild: {
  minifyWhitespace: true
}

explicitly in their vite config.

[WIStudent]

I opened a pull request that would make it possible to re-enable whitespace minification by setting

esbuild: {
  minifyWhitespace: true
}

[dteoh]

At the moment I've been using this kind of config instead of lib mode to serve ESM in a CDN-like manner:

export default defineConfig({
  build: {
    rollupOptions: {
      input: resolve(__dirname, "src/index.js"),
      output: {
        assetFileNames: (chunkInfo) => {
          return "[name][extname]";
        },
        entryFileNames: "[name].js",
      },
      preserveEntrySignatures: "strict",
    },
    sourcemap: true,
  },
});

Seems to work, but I am also not sure if I am missing some key information regarding why we cannot minify in lib mode.