Menu
Facebook's Flow could help JavaScript programmers spot elusive bugs

Facebook's Flow could help JavaScript programmers spot elusive bugs

Flow offers much-needed static type checking for the JavaScrtipt language

Easing what has traditionally been a difficult programming task, Facebook has released as open source a debugging tool for JavaScript, called Flow, designed to highlight problems caused by the misuse of data types.

"Flow improves speed and efficiency so developers can be more productive while using JavaScript," Facebook engineers said in a blog item posted Tuesday. Facebook has used Flow for many of its own projects.

Flow is a static type checker, one that ensures that when a program is run that its variables, functions and other elements of code will adhere to their original specifications. It can check to see if a value assigned to a variable is the correct type, for instance, a number rather than a string of characters. It can also check to see if a function is passed the correct number of inputs.

Such error checks could prevent program failures, and help secure the program against malicious misuse. Type checking can also aid in maintaining the program's code base.

JavaScript has grown increasingly popular in the past few years as a Web development tool, not only for adding functionality to Web pages, but also for creating full-scale Web applications. Unlike more traditional programming languages such as C++, JavaScript does not provide any native static typing capabilities. Because it is a very expressive language, JavaScript does not lend itself easily to type-checking systems, the Facebook engineers wrote.

Other companies have tackled the challenge of adding static type checking to JavaScript. Microsoft, for instance, developed TypeScript, a superset of JavaScript code that can be compiled so type checks can be conducted.

Unlike TypeScript, Flow allows the developer to check only portions of the code. JavaScript frameworks often use techniques, such as reflection, that make it difficult to use type checking.

Running Flow does not require the programmer to compile the program, or otherwise prepare the program for inspection. Instead, it works as a background process. Flow can check standard primitive types such as numbers, strings, and Boolean values as well as structured types such as functions, objects, and arrays.

Flow is initially available as a plug-in for both the Emacs and Vim code editors, and versions for other editors may be released in the future. It also offers a API (application programming interface) so it can be used by other code analysis tools.

Facebook will routinely release tools as open source that company engineers originally developed for internal use, in hopes that others will further develop the tools. The company has released a virtual machine for running programs written in PHP, called the Hip Hop Virtual Machine. It has also released a popular JavaScript library for building user interfaces, called React, and a database engine for querying distributed sets of data, called Presto.

Joab Jackson covers enterprise software and general technology breaking news for The IDG News Service. Follow Joab on Twitter at @Joab_Jackson. Joab's e-mail address is Joab_Jackson@idg.com


Follow Us

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags Facebooksoftwareapplication developmentDevelopment tools

Featured

Slideshows

EDGE 2018: Kiwis kick back with Super Rugby before NZ session

EDGE 2018: Kiwis kick back with Super Rugby before NZ session

New Zealanders kick-started EDGE 2018 with a bout of Super Rugby before a dedicated New Zealand session, in front of more than 50 partners, vendors and distributors on Hamilton Island.​

EDGE 2018: Kiwis kick back with Super Rugby before NZ session
EDGE 2018: Kiwis assess key customer priorities through NZ research

EDGE 2018: Kiwis assess key customer priorities through NZ research

EDGE 2018 kicked off with a dedicated New Zealand track, highlighting the key customer priorities across the local market, in association with Dell EMC. Delivered through EDGE Research - leveraging Kiwi data through Tech Research Asia - more than 50 partners, vendors and distributors combined during an interactive session to assess the changing spending patterns of the end-user and the subsequent impact to the channel.

EDGE 2018: Kiwis assess key customer priorities through NZ research
Show Comments