Registry / devops / flow-babel-webpack-plugin

flow-babel-webpack-plugin

library1.1.1jsnpmunverified

Flow Babel Webpack Plugin (v1.1.1, last released in 2017) is a Webpack plugin that integrates Flow type checking into the Webpack build process using Babel to strip type annotations via transform-flow-comments. It provides real-time Flow error or warning reports in the Webpack output. Unlike alternatives like flow-webpack-plugin or babel-plugin-transform-flow-strip-types, this plugin specifically works with the transform-flow-comments approach to preserve type annotations as comments for Flow checks, while also allowing custom error formatting and warning-only mode. The package has not been updated in years and likely has compatibility issues with modern Webpack (4/5) and Babel (7+); it targets Webpack 1.x/2.x and Babel 6.

devops

npm install flow-babel-webpack-plugin

github ↗package ↗

INSTALL

IMPORT

SIG · FLOW-BABEL-WEBPACK

flow-babel-webpack-plugin

devopsjavascriptv1.1.1

Install

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Import

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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

✓ const FlowBabelWebpackPlugin = require('flow-babel-webpack-plugin');

✗ import FlowBabelWebpackPlugin from 'flow-babel-webpack-plugin';

Package does not export named exports or support ESM. Use CommonJS require().

FlowBabelWebpackPlugin

✓ const FlowBabelWebpackPlugin = require('flow-babel-webpack-plugin'); const plugin = new FlowBabelWebpackPlugin({ warn: true });

✗ const { FlowBabelWebpackPlugin } = require('flow-babel-webpack-plugin');

Only default export is available. Destructuring will fail.

new FlowBabelWebpackPlugin()

✓ plugins: [ new FlowBabelWebpackPlugin() ]

✗ plugins: [ FlowBabelWebpackPlugin ]

Must instantiate with new. Passing the class reference will not work.

Shows setup of .babelrc and webpack.config.js to run Flow type checking via Webpack plugin.

// Install dependencies // npm i -D babel-core@6 babel-loader@7 webpack@2 babel-plugin-transform-flow-comments flow-babel-webpack-plugin // .babelrc { "plugins": ["transform-flow-comments"] } // webpack.config.js const FlowBabelWebpackPlugin = require('flow-babel-webpack-plugin'); module.exports = { entry: './index.js', output: { filename: 'build.js' }, module: { loaders: [ { test: /\.js$/, loader: 'babel' } ] }, plugins: [ new FlowBabelWebpackPlugin({ warn: false, formatter: function (errorCode, errorDetails) { return 'Flow error ' + errorCode + ': ' + errorDetails; } }) ] };

Debug

Known issues

breakingThis plugin only works with Webpack v1.x or v2.x. Webpack v4/v5 use different plugin API and this plugin will fail silently or throw errors.

fix

Migrate to flow-webpack-plugin (if available) or remove this plugin and run Flow separately via CLI or script.

affects: >=1.0.0

gotchaRequires babel-plugin-transform-flow-comments to be in .babelrc; using babel-plugin-transform-flow-strip-types will strip type annotations and Flow will not run.

fix

Ensure .babelrc contains 'transform-flow-comments' (not 'transform-flow-strip-types').

affects: >=1.0.0

deprecatedPackage is not maintained since 2017; no support for Babel 7, Webpack >=3, or Flow >=0.80.

fix

Consider using alternative tools like 'flow-remove-types' or running Flow separately.

affects: >=1.0.0

gotchaIf Flow is not installed globally or in node_modules, the plugin will fail with 'flow: not found' error.

fix

Install flow-bin as a devDependency: npm i -D flow-bin and ensure node_modules/.bin is in PATH when running webpack.

affects: >=1.0.0

gotchaThe plugin does not support options like failOnError (only 'warn' boolean).

fix

Handle errors differently if needed; no alternative option available.

affects: >=1.0.0

Errors

Common errors & fixes

Error: Cannot find module 'flow-babel-webpack-plugin'

Package not installed or typo in package name.

fix

Run 'npm install flow-babel-webpack-plugin' (note: it's not 'flow-babel-webpack', missing hyphen).

TypeError: FlowBabelWebpackPlugin is not a constructor

Using import/require incorrectly; the plugin exports a single constructor, but attempting destructuring or using without 'new'.

fix

Use: const FlowBabelWebpackPlugin = require('flow-babel-webpack-plugin'); new FlowBabelWebpackPlugin();

Module build failed: Error: Cannot find module 'babel-plugin-transform-flow-comments'

Missing babel-plugin-transform-flow-comments in devDependencies or .babelrc references it incorrectly.

fix

Run 'npm install --save-dev babel-plugin-transform-flow-comments' and ensure .babelrc contains the plugin.

flow: command not found

Flow is not installed or not in PATH when webpack runs.

fix

Add 'flow-bin' as devDependency and run webpack from project root where node_modules/.bin is accessible.

Unhandled 'error' event: Error: spawn flow ENOENT (or similar)

Flow binary not found or not executable.

fix

Ensure flow-bin is installed: npm install --save-dev flow-bin; also check that 'flow' works from command line in project directory.

Upgrade

Version history

1.1.1latest on npm

Audit

Dependencies

babel-corerequiredRequired for Babel transformation in Webpack pipeline

babel-loaderrequiredRequired to run Babel in Webpack

webpackrequiredRequires Webpack v1.x or v2.x; not compatible with v3+

babel-plugin-transform-flow-commentsrequiredRequired to convert Flow type annotations into comments

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/zhirzh/flow-babel-webpack-plugin ↗

packagehttps://www.npmjs.com/package/flow-babel-webpack-plugin ↗