rollup-plugin-flow

1.1.1 verified Mon Apr 27 auth: no javascript maintenance

A Rollup plugin to strip Flow type annotations from JavaScript/Flow files before bundling, using flow-remove-types under the hood. Current stable version is 1.1.1, with minimal maintenance cadence. It transforms files containing @flow comments by default, with an option to process all files. Provides a 'pretty' mode that removes types without adding whitespace. Differentiators: lightweight and fast compared to full Flow transformation; does not require Flow itself to run; integrates seamlessly with Rollup's build pipeline.

Common errors

error Error: Cannot find module 'flow-remove-types' ↓

cause flow-remove-types is not installed

fix

npm install flow-remove-types --save-dev

error TypeError: flow is not a function ↓

cause Using an older version of the plugin where default export was an object

fix

Update to version 1.1.1 and call flow() instead of just flow

error The plugin does nothing — no types removed ↓

cause Files do not contain @flow comment; `all` option not set

fix

Add @flow comment to files or set all: true in plugin options

error Unexpected token ':' ↓

cause Flow syntax not stripped before bundling; plugin not included or misconfigured

fix

Ensure rollup-plugin-flow is added to plugins array and called correctly

Warnings

gotcha Flow transformation is applied before bundling, so it cannot be combined with other transforms that depend on flow annotations. ↓

fix Ensure this plugin is first in the plugins array if other plugins should see untyped code; else place after Babel if Babel should handle Flow.

gotcha The plugin does not type-check the code; it only removes annotations. For type checking, run Flow separately. ↓

fix Run flow check as a separate step before bundling.

breaking In version 1.1.0, the default export changed from an object to a function. Old usage `plugins: [flow]` will break; must call `flow()` ↓

fix Change `plugins: [flow]` to `plugins: [flow()]` or `plugins: [require('rollup-plugin-flow')()]`

deprecated Rollup changed its plugin API; the plugin expects a `transform` hook that receives `{code, map}`, not `source` ↓

fix Update rollup to a version compatible with the plugin's API (rollup <0.50)

gotcha When using `pretty: true`, source maps are recommended but not generated by default; output may have incorrect line mappings. ↓

fix Set `sourcemap: true` in rollup config and provide input sourcemap if available.

Install

npm install rollup-plugin-flow

yarn add rollup-plugin-flow

pnpm add rollup-plugin-flow

Imports

default
wrong
```
const flow = require('rollup-plugin-flow');
```
correct
```
import flow from 'rollup-plugin-flow'
```
CommonJS require still works in older versions; this is the default export
flow function
wrong
```
import { flow } from 'rollup-plugin-flow'
```
correct
```
import flow from 'rollup-plugin-flow';
plugins: [ flow({ all: true }) ]
```
The package exports a single function as default export, not a named export. Named import will be undefined.

usage in rollup config

wrong

plugins: [ { transform: ... } ]

correct

import flow from 'rollup-plugin-flow';
export default {
  input: 'src/index.js',
  plugins: [flow()]
}

Must call the imported function to create the plugin instance.

Quickstart

Basic usage: import the default export, call it with options, pass as plugin to Rollup.

import flow from 'rollup-plugin-flow';
import { rollup } from 'rollup';

const bundle = await rollup({
  input: 'src/index.js',
  plugins: [
    flow({
      all: true,
      pretty: false
    })
  ]
});

const { output } = await bundle.generate({ format: 'esm' });
console.log(output[0].code);