PostsNaive Typescript Conversion on RichSoni.com: Pass 3
Posted 01/03/2019

This is the third pass of converting this site to Typescript.

Previous Posts

Experiment Parameters

  1. Convert all javascript files in src/components to typescript
  2. Must include: a post with content from this document

Strategy

This was a simple exercise, I renamed all of the files from jsx -> tsx and js -> ts. Then I ran my server, and fixed all of the errors.

Outcome

$ ./scripts/typescript-vs-javascript
68% (28 Typescript / 13 Javascript)

Summary Of Changes

$ git diff --stat master
 package.json                                               |  1 +
 src/components/Content/{index.jsx => index.tsx}            |  4 ++--
 src/components/EventIndex/{index.js => index.tsx}          |  7 +++---
 src/components/FixedMenu/{index.js => index.tsx}           | 15 ++++++++-----
 src/components/Footer/{index.js => index.tsx}              |  2 +-
 src/components/LatestRelease/{index.jsx => index.tsx}      | 38 ++++++++++++++++++++++----------
 src/components/Layout/{index.js => index.tsx}              | 12 +++++++---
 src/components/Logo/{index.js => index.tsx}                |  6 ++---
 src/components/MailingListHalf/{index.js => index.tsx}     |  2 +-
 src/components/MenuToggle/{index.js => index.tsx}          | 22 +++++++++++--------
 src/components/OverlayMenu/{index.js => index.tsx}         |  4 ++--
 src/components/ResponsiveMenu/{index.js => index.tsx}      | 16 +++++++++-----
 src/components/SocialButton/{index.js => index.tsx}        | 27 +++++++++++------------
 src/components/Table/index.tsx                             | 11 ++++++----
 src/posts/2019-01-03-naive-typescript-conversion-pass-3.md | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 yarn.lock                                                  |  5 +++++
 16 files changed, 183 insertions(+), 65 deletions(-)

Learnings

I learned a few important things during this phase of the conversion. I expect these learnings to be useful in future passes.

JSX Requires the proper extension in Typescript

src/components/Footer/index.ts(8,5): error TS1005: '>' expecte

This was an error I saw a lot because I used to only use .js for jsx files.

Pure Function Components

I write a lot of components in a pure functional form:

export default (props) =>{
 return <div>{props.children}</div>
}

React comes with a special typing for these functions:

type Props = {
  children: JSX.Element,
}
const Component: React.SFC<Props> = (props) => {
  return <div>{this.props.children}</div>
}
export default Component

Optional Attributes

I used a lot of optional attributes on props. To make an attribute optional, add a ? after its key:

type Props = {
  requiredProp: boolean,
  optionalProp?: boolean,
}

Improvements

Vim Plugin

I added a vim plugin called tsuquyomi, which leverages the TSServer to do a lot of neat things. In this case, I used the quickfix list population facility to quickly navigate to failing tsc lines.

Error Catching

A few significant type errors where caught by Typescript in this commit. One was a component expecting a boolean value for a prop, and a string was being passed.

A few unneeded props where detected as well.

Conclusion

At this point I am starting to get value out of using Typescript. The code quality of the project has improved, and my productivity has potential gains through leveraging omnicomplete.

One thing I would like to note is that during this pass, I started to flesh out more types when I was feeling inspired. I can see how writing new components will be easier with Typescript for sure.