Registry / devops / babel-preset-proposals

babel-preset-proposals

library0.4.0jsnpmunverified

A Babel 7 preset that manages experimental proposal plugin dependencies, ordering, and default options. Current version 0.4.0 (released 2021-02-24), requires Node >=10. Key differentiators: automatically handles plugin ordering and option defaults for decorators and pipeline operator, removes plugins handled by @babel/preset-env, and supports all major TC39 proposals via boolean or object configuration. Release cadence is irregular; last release was over 3 years ago. Notable changes include removal of jsonStrings/nullishCoalescingOperator/optionalChaining options in v0.2.0 and addition of classStaticBlock in v0.4.0. This preset helps avoid common misconfigurations of Babel proposal plugins.

devops

npm install babel-preset-proposals

github ↗package ↗

INSTALL

IMPORT

SIG · BABEL-PRESET-PROPO

babel-preset-proposals

devopsjavascriptv0.4.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

default

✓ module.exports = require('babel-preset-proposals')

✗ import preset from 'babel-preset-proposals'

This is a CommonJS package; use require() in Node.js or configure in .babelrc/babel.config.js as a preset string.

validateOptions

✓ const { validateOptions } = require('babel-preset-proposals')

✗ import { validateOptions } from 'babel-preset-proposals'

validateOptions is exported as a named export in CommonJS; destructure from require().

PresetOptions

✓ // No TypeScript types shipped; define your own interface

✗ import { PresetOptions } from 'babel-preset-proposals'

This package does not provide TypeScript type definitions. You must create your own type for options.

Shows both .babelrc JSON configuration and programmatic CommonJS usage with options like classProperties, decorators, and loose mode.

// Install: npm install babel-preset-proposals // .babelrc or babel.config.js { "presets": [ ["babel-preset-proposals", { "classProperties": true, "decorators": { "legacy": true }, "exportDefaultFrom": true, "numericSeparator": true, "loose": true }] ] } // Programmatic usage (Node.js CJS): const proposalsPreset = require('babel-preset-proposals'); const babel = require('@babel/core'); const result = babel.transformSync('code', { presets: [[proposalsPreset, { classProperties: true }]] }); console.log(result.code);

Debug

Known issues

breakingRemoved options jsonStrings, nullishCoalescingOperator, optionalChaining; these plugins are now handled by @babel/preset-env (v0.2.0).

fix

Remove these options from preset config; enable via @babel/preset-env's targets or use the plugins directly if needed.

affects: >=0.2.0

breakingDecorators default changed from {legacy: true} to no default; you must explicitly specify {legacy: true} to preserve old behavior (v0.2.0).

fix

Update preset config: replace 'decorators: true' with 'decorators: {legacy: true}' for legacy behavior.

affects: >=0.2.0

breakingNode.js 8 required; dropped support for Node 6 (v0.3.0). v0.4.0 requires Node >=10.

fix

Upgrade Node.js to version 10 or higher for v0.4.0.

affects: >=0.3.0

deprecatedSome proposal plugins like classPrivateMethods and staticClassFeatures are not included; users must add them manually.

fix

Add missing plugins individually, e.g., @babel/plugin-proposal-private-methods.

affects: *

gotchaUsing absolutePaths: true is required if the config is used outside the project's node_modules scope; otherwise Babel may fail to resolve plugins.

fix

Set absolutePaths: true if generating config for external consumption or using with tools like Webpack's babel-loader.

affects: *

Errors

Common errors & fixes

Error: [BABEL] unknown preset: 'babel-preset-proposals'

Package not installed or not in node_modules path.

fix

Run 'npm install babel-preset-proposals' and ensure your .babelrc is in the project root.

Error: Plugin .option is not a valid Plugin property

Passed options not recognized by the preset, e.g., 'optionalChaining: true' in v0.2.0+.

fix

Check the README for valid options; for removed options, use @babel/preset-env or the plugin directly.

TypeError: Cannot read property 'replace' of undefined

Using preset with an invalid option value (e.g., passing a string instead of boolean/object).

fix

Ensure each option is either boolean or an Object as documented.

Upgrade

Version history

0.4.0latest on npm

Audit

Dependencies

@babel/corerequiredPeer dependency required for Babel presets to function

@babel/plugin-proposal-class-propertiesoptionalRequired plugin for class properties proposal

@babel/plugin-proposal-decoratorsoptionalRequired plugin for decorators proposal

@babel/plugin-proposal-pipeline-operatoroptionalRequired plugin for pipeline operator proposal

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/insin/babel-preset-proposals ↗

packagehttps://www.npmjs.com/package/babel-preset-proposals ↗