Registry / serialization / babel-plugin-flow-to-typescript

babel-plugin-flow-to-typescript

library0.6.0jsnpmunverified

Babel plugin to convert Flow type annotations into TypeScript. Current stable version: 0.6.0. Release cadence is low (last release June 2018). Key differentiator: transforms Flow syntax (exact types, opaque types, $Keys, etc.) directly in Babel pipeline. No type inference, but covers most Flow constructs including maybe types, function types, object types, and utility types like $Diff and $Shape. Requires @babel/core ^7.4.4. Not actively maintained; no support for newer Flow features or TypeScript 3+ syntax.

serialization

npm install babel-plugin-flow-to-typescript

github ↗package ↗

INSTALL

IMPORT

SIG · BABEL-PLUGIN-FLOW-

babel-plugin-flow-to-typescript

serializationjavascriptv0.6.0

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.

plugin

✓ { plugins: ['babel-plugin-flow-to-typescript'] }

✗ { plugins: [require('babel-plugin-flow-to-typescript')] }

Add to Babel config as a plugin string. With @babel/core 7+, use the string name.

module/require usage

✓ const plugin = require('babel-plugin-flow-to-typescript');

✗ import plugin from 'babel-plugin-flow-to-typescript';

CommonJS require works; ESM default import may fail if package lacks 'default' export.

Babel config (babel.config.js)

✓ module.exports = { plugins: ['babel-plugin-flow-to-typescript'] };

Standard Babel config file. No special syntax.

Converts a Flow function with maybe type (?string) to TypeScript union with null and undefined.

// Install CLI and plugin // npm install -g @babel/cli @babel/core // npm install babel-plugin-flow-to-typescript // Run conversion on a Flow file // babel --plugins babel-plugin-flow-to-typescript input.js -o output.ts // Example input (Flow): // // @flow // function greet(name: ?string): string { // return 'Hello ' + (name || 'world'); // } // Example output (TypeScript): function greet(name: string | null | undefined): string { return 'Hello ' + (name || 'world'); }

Debug

Known issues

breakingRequires @babel/core ^7.4.4. Older versions may fail.

fix

Update @babel/core to ^7.4.4 or later.

affects: <7.4.4

deprecatedUnmaintained since June 2018. No support for TypeScript 3+ features or newer Flow syntax like $ReadOnlyArray.

fix

Consider using flow-to-typescript or a manual migration script for modern Flow/TypeScript.

affects: 0.6.0

gotchaDoes not handle Flow import type syntax fully; import type A from 'module' becomes import A from 'module' (removes type-only), which may cause runtime errors if module has no default export.

fix

Manually review imports after conversion; use type-only imports in TypeScript with 'import type'.

affects: >=0.3.0

gotchaTransforms $FlowFixMe to any, which may hide real type errors.

fix

Replace $FlowFixMe comments with TypeScript's '// @ts-ignore' or proper types manually.

affects: >=0.2.0

Errors

Common errors & fixes

Error: Cannot find module '@babel/core'

@babel/core not installed or wrong version.

fix

npm install --save-dev @babel/core@^7.4.4

TypeError: Cannot read property 'convert' of undefined

Plugin not found or incorrectly referenced in Babel config.

fix

Ensure plugin is installed and string name used in plugins array: 'babel-plugin-flow-to-typescript'

SyntaxError: Unexpected token (1:8) - You may need an appropriate loader to handle this file type.

Babel not configured to handle Flow syntax before conversion.

fix

Add '@babel/preset-flow' or '@babel/plugin-syntax-flow' before this plugin in plugins array.

Upgrade

Version history

0.6.0latest on npm

Audit

Dependencies

@babel/corerequiredRequired as Babel plugin

Agent activity

11 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/Kiikurage/babel-plugin-flow-to-typescript ↗

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