Flow (JS) vs Pyright

Overview

Flow (JS)

Stacks145

Followers75

Votes0

GitHub Stars22.2K

Forks1.9K

Pyright

Stacks36

Followers31

Votes0

GitHub Stars14.9K

Forks1.7K

Flow (JS) vs Pyright: What are the differences?

Flow (JS): Flow is a static type checker for Javascript (by Facebook). Flow is a static type checker for Javascript created by Facebook; Pyright: Static type checker for the Python language by Microsoft. Typically 5x or more faster than mypy and other type checkers that are written in Python. It is meant for large Python source bases. It can run in a “watch” mode and performs fast incremental updates when files are modified.

Flow (JS) and Pyright can be categorized as "Static Type Checkers" tools.

Some of the features offered by Flow (JS) are:

Type Inference
Easy Integration
Realtime Feedback

On the other hand, Pyright provides the following key features:

Hover tool tips that display type information
Links to symbol definitions
Smart priority queuing for interactive feedback during editing

Flow (JS) and Pyright are both open source tools. It seems that Flow (JS) with 19.7K GitHub stars and 1.68K forks on GitHub has more adoption than Pyright with 4.21K GitHub stars and 138 GitHub forks.

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Advice on Flow (JS), Pyright

StackShare

Aug 13, 2019

Needs adviceon

TypeScript

CoffeeScript

JavaScript

From a StackShare community member: "We are looking to rewrite our outdated front-end with TypeScript. Right now we have a mix of CoffeeScript and vanilla JavaScript. I have read that adopting TypeScript can help enforce better code quality, and best practices. I also heard good things about Flow (JS). Which one would you recommend and why?"

405k views405k

Comments

Oleksandr

Senior Software Engineer at joyn

Oct 21, 2019

Decided

Initially making a decision to use Flow vs Typescript we decided to go with flow as we wanted our code to run in a way we wrote it, because when using Flow types are simply removed from the code without modifying the code itself. Sadly, the type system of Flow was in some cases very hard to understand and declare the types correctly, especially in cases when the structure is very dynamic (e.g. object keys and values are created dynamically). Another reason was bad integration with IDE and frequent crashes which made DX very poor. Therefore, we made another evaluation of Typescript and decided to move towards it. As our code base was pretty big when we decided to migrate to TS we couldn't just stop and re-write everything, that's why we started writing new modules in Typescript as well as transforming old components. To make that possible we had to configure Webpack loader to support simultaneous bundling of Flow&JS and Typescript. After around 2 months of the transformation we have around 40% of code being written in Typescript and we are more than happy with integration TS has with IDE, as well as ease of declaring types for dynamic modules and functions.

149k views149k

Comments

Vladyslav

Sr. Directory of Technology at Shelf

Oct 25, 2019

Decided

As our codebase grew in size, we were looking for ways to improve code quality. We chose TypeScript over Flow due to its rapid industry adoption and overall tools support.

We noticed how different open-source projects were migrating from Flow to TypeScript. Most notably, it was Jest, even though Jest and Flow were both developed by Facebook. See this HN thread if you want to dive into an interesting discussion around this move.

Additionally, at the beginning of 2019, both Babel and ESLint enabled seamless TypeScript support, which allowed easy migration path in a backward-compatible way.

155k views155k

Comments

Detailed Comparison

Flow (JS)	Pyright
Flow is a static type checker for Javascript created by Facebook.	Typically 5x or more faster than mypy and other type checkers that are written in Python. It is meant for large Python source bases. It can run in a “watch” mode and performs fast incremental updates when files are modified.
Type Inference; Easy Integration; Realtime Feedback	Hover tool tips that display type information; Links to symbol definitions; Smart priority queuing for interactive feedback during editing
Statistics
GitHub Stars 22.2K	GitHub Stars 14.9K
GitHub Forks 1.9K	GitHub Forks 1.7K
Stacks 145	Stacks 36
Followers 75	Followers 31
Votes 0	Votes 0
Integrations
No integrations available	Node.js Python Visual Studio Code TypeScript GNU Bash

What are some alternatives to Flow (JS), Pyright?

CoffeeScript

It adds syntactic sugar inspired by Ruby, Python and Haskell in an effort to enhance JavaScript's brevity and readability. Specific additional features include list comprehension and de-structuring assignment.

TypeScript

TypeScript is a language for application-scale JavaScript development. It's a typed superset of JavaScript that compiles to plain JavaScript.

Pug

This project was formerly known as "Jade." Pug is a high performance template engine heavily influenced by Haml and implemented with JavaScript for Node.js and browsers.

Handlebars.js

Handlebars.js is an extension to the Mustache templating language created by Chris Wanstrath. Handlebars.js and Mustache are both logicless templating languages that keep the view and the code separated like we all know they should be.

Mustache

Mustache is a logic-less template syntax. It can be used for HTML, config files, source code - anything. It works by expanding tags in a template using values provided in a hash or object. We call it "logic-less" because there are no if statements, else clauses, or for loops. Instead there are only tags. Some tags are replaced with a value, some nothing, and others a series of values.

Slim Lang

Slim is a template language whose goal is to reduce the view syntax to the essential parts without becoming cryptic. It started as an exercise to see how much could be removed from a standard html template (<, >, closing tags, etc...). As more people took an interest in Slim, the functionality grew and so did the flexibility of the syntax.

RactiveJS

Ractive was originally created at theguardian.com to produce news applications. Ractive takes your Mustache templates and transforms them into a lightweight representation of the DOM – then when your data changes, it intelligently updates the real DOM.

EJS

It is a simple templating language that lets you generate HTML markup with plain JavaScript. No religiousness about how to organize things. No reinvention of iteration and control-flow. It's just plain JavaScript.

Jinja

It is a full featured template engine for Python. It has full unicode support, an optional integrated sandboxed execution environment, widely used and BSD licensed.