babel-preset-optimizations

2.0.0 verified Sat Apr 25 auth: no javascript

Babel preset that bundles babel-minify optimisation plugins for production builds. Version 2.0.0 requires Node >=10.13.0 and ships TypeScript types. It includes plugins for constant folding, dead code elimination, guarded expressions, inline consecutive adds, undefined-to-void, and optionally simplify. Unlike full minifiers, it focuses solely on optimisations without mangling or compression, giving finer control over the output. Options allow preserving function/class names and enabling simplify or undefined-to-void transforms. It is best used alongside a separate minification step.

Common errors

error Error: Plugin/Preset files are not allowed to export objects, only functions. ↓

cause Using an outdated Babel version or wrong import syntax for the preset.

fix

Ensure Babel is version 7 and use the correct preset reference: 'babel-preset-optimizations' or short name 'optimizations'.

error Module not found: Can't resolve 'babel-preset-optimizations' ↓

cause Package not installed or not properly resolved.

fix

Run 'npm install --save-dev babel-preset-optimizations' and check node_modules.

error Unknown option: keepFnName ↓

cause Options object passed incorrectly – not wrapped in an array.

fix

Use [['optimizations', { keepFnName: true }]] instead of ['optimizations', { keepFnName: true }].

Warnings

gotcha This preset does not minify or mangle code; it only applies optimisations. Use alongside a minifier like babel-minify or terser. ↓

fix Add 'minify' or another minification preset/plugin after this one.

deprecated The simplify option changes code structure significantly and may be considered harmful for debugging. ↓

fix Only enable simplify in production builds with source maps, or avoid it.

gotcha Options must be passed in the nested array format for presets, not as a flat array. ↓

fix Use [["optimizations", { options }]] instead of ["optimizations", { options }].

breaking Version 2.0.0 drops support for Node <10.13.0. ↓

fix Upgrade Node to >=10.13.0 or stick with v1.x.

gotcha In Babel 7, preset short names may not resolve automatically; you might need the full package name. ↓

fix Use 'babel-preset-optimizations' instead of 'optimizations' if short name fails.

Install

npm install babel-preset-optimizations

yarn add babel-preset-optimizations

pnpm add babel-preset-optimizations

Imports

babel-preset-optimizations

wrong

require('babel-preset-optimizations') as a plugin

correct

module.exports = { presets: ['optimizations'] }; or in .babelrc: { "presets": ["optimizations"] }

It is a preset, not a plugin. Use in presets array with short name 'optimizations'.

options object

wrong

{"presets": ["optimizations", { "keepFnName": false }]}

correct

{"presets": [["optimizations", { "keepFnName": false }]]}

Options must be in a nested array: [ ["presetName", options] ].

require() in Node API

wrong

const preset = require('babel-preset-optimizations').default;

correct

const preset = require('babel-preset-optimizations');

The package exports the preset function directly; no default export needed.

Quickstart

Shows how to enable the preset with default options in a Babel configuration file.

// .babelrc or babel.config.js
module.exports = {
  presets: [
    ['optimizations', {
      keepFnName: true,
      keepClassName: true,
      simplify: false,
      undefinedToVoid: false
    }]
  ]
};