JSFoo 2017

JSFoo is a conference about JavaScript and everything related.

Vagmi Mudumbai


Type check your JS codebase with Flow

Submitted Apr 22, 2017

Flow is a static type checker for Javascript. By adding a few type annotations Flow lets you minimize errors that can occur in a large codebase. By the end of this talk we’ll look at common anti-patterns with JS codebases and how Flow can help you write better code.


  • Introduce flow with a simple hello world example.
  • Introduce comment type vs inline annotations
  • Introduce MaybeTypes to address the billion dollar mistake
  • Touch upon Classes, Function Types, Generics and Union Types
  • Live code a small example to demonstrate editor integration such as autocomplete and inline errors and demonstrate Flow works well with Babel and eslint.
  • Introduce flow-typed to obtain type annotations for popular npm libraries
  • Q&A

Speaker bio

I have been writing Javascript for several years now and have relied on tools such as linters and unit testing to catch bugs. Flow is one more tool in JS developers toolbelt that is essential for today’s single page app JS world regardless of which framework or library you use.


{{ gettext('Login to leave a comment') }}

{{ gettext('Post a comment…') }}
{{ gettext('New comment') }}
{{ formTitle }}

{{ errorMsg }}

{{ gettext('No comments posted yet') }}