I moved a 4000 line coffeescript project to typescript and I liked it
TLDR: jump straight to the TypeScript section
About 8 months ago I started a new complex web app in javascript, and it quickly grew out of hand.
It had:
Someone recommended CoffeeScript and I went with it.
The codebase expanded to about 4000 LOC in a matter of weeks.
Pros:
I compiled all the .coffee files to .js files, removed all the .coffee files from the repo, and renamed all the .js files to .ts. Technically I was already done, as js is a strict subset of typescript, but doing everything typescript style was a bit more work.
Here are my experiences.
Pros:
I really really really like TypeScript. My project feels really clean, I see lots of room for improvement (and this time I know where to start). For larger codebases typescript will greatly improve maintainability.
If you work on a large codebase you can either automate testing, enforce developer discipline or move to static typing and a compile step. I think the last option is greatly preferred.
About 8 months ago I started a new complex web app in javascript, and it quickly grew out of hand.
It had:
- a server with routes
- a singleton object with state, logic and helper functions
- a bunch of similar plugins that extend functionality
- the singleton object lives both on the server and on the client
Someone recommended CoffeeScript and I went with it.
The codebase expanded to about 4000 LOC in a matter of weeks.
So CoffeeScript hm, what about it?
These are my experiences after maintaining a non-trivial coffeescript application for a couple of months.
- Programming was quicker, stuff you want is already in the language. (classes, inheritance, array comprehension, filters)
- Less verbose.
- for k,v in object
- fat arrow
- "string interpolation #{yes.please}"
- fat arrow is very similar to thin arrow, git diff thinks this sucks
- syntax. The attempt of avoiding braces is horrible. Function calling is a mess.
- It smells like ruby. I dislike ruby with a vengeance.
- no more var keyword? This is disturbing and error prone, given its significant subtleties in javascript.
- everything is an expression? I like to be explicit about return values kthnxbye.
TypeScript
When I started this codebase TypeScript had just launched. I deemed it a bit too experimental to work with, but last weekend I decided to give it a go. On Sunday I did git checkout -b typescript-conversion, installed the typescript syntastic plugins and started up vim. Fourteen straight hours of refactoring later it was done and 4238 lines of coffeescript had turned into 6145 lines of typescript.I compiled all the .coffee files to .js files, removed all the .coffee files from the repo, and renamed all the .js files to .ts. Technically I was already done, as js is a strict subset of typescript, but doing everything typescript style was a bit more work.
Here are my experiences.
Pros:
- fat arrow: removed almost all uses of self = this.
- static type and function signature checking. I immedeately fixed about ten hidden bugs thanks to this.
- classes and modules have never been easier
- linking using
tags - compiling linked files to one concatenated file out of the box using tsc --out
- aim at ecmascript 6 forwards compatibility
- slower tooling (vim syntastic takes about 3-5 seconds after each buffer save)
- no way of doing stuff like for k, v in object
- no string interpolation
- no automatic ecmascript 3 compatibility layer (monkeypatching Array with indexOf etc.)
Conclusion
I really really really like TypeScript. My project feels really clean, I see lots of room for improvement (and this time I know where to start). For larger codebases typescript will greatly improve maintainability.
If you work on a large codebase you can either automate testing, enforce developer discipline or move to static typing and a compile step. I think the last option is greatly preferred.