@babel/plugin-transform-flow-strip-types

What is @babel/plugin-transform-flow-strip-types?

The @babel/plugin-transform-flow-strip-types npm package is a plugin for Babel, a JavaScript compiler, that removes type annotations from Flow, a static type checker for JavaScript. This allows developers to write type-safe code during development and strip out these annotations for production builds, resulting in clean JavaScript that can be executed in environments that do not support Flow.

What are @babel/plugin-transform-flow-strip-types's main functionalities?

Stripping Flow Type Annotations

This feature removes Flow type annotations from your JavaScript files, converting typed code into plain JavaScript. The code sample shows a function with Flow types that are stripped out after transformation.

import { foo } from 'bar';
function square(n: number): number {
  return n * n;
}
// Transformed to:
import { foo } from 'bar';
function square(n) {
  return n * n;
}

Other packages similar to @babel/plugin-transform-flow-strip-types

@babel/plugin-transform-typescript

Similar to @babel/plugin-transform-flow-strip-types, this Babel plugin strips TypeScript annotations from the code. While both plugins serve a similar purpose of removing type annotations, they cater to different type systems: Flow for the former and TypeScript for the latter.

babel-plugin-transform-flow-comments

This plugin also deals with Flow types but instead of stripping them, it converts them into comments. This can be useful for preserving type annotations in the transpiled output without affecting the runtime behavior.

README

@babel/plugin-transform-flow-strip-types

Strip all flow type annotations and declarations from your output code.

Example

In

function foo(one: any, two: number, three?): string {}

Out

function foo(one, two, three) {}

Installation

npm install --save-dev @babel/plugin-transform-flow-strip-types

Usage

Via .babelrc (Recommended)

.babelrc

{
  "plugins": ["@babel/plugin-transform-flow-strip-types"]
}

Via CLI

babel --plugins @babel/plugin-transform-flow-strip-types script.js

Via Node API

require("@babel/core").transform("code", {
  plugins: ["@babel/plugin-transform-flow-strip-types"]
});

Options

requireDirective

boolean, defaults to false.

Setting this to true will only strip annotations and declarations from files that contain the // @flow directive. It will also throw errors for any Flow annotations found in files without the directive.