Learn to wield promises like a master to write clean asynchronous code
Uses ECMAScript 6 Promises
Promises offer a very powerful abstraction for obtaining values asynchronously.
You will learn the ins and outs of promises including error handling, value propagation, synchronous returns, and composition.
By the end of the workshop you will be comfortable using ES6 promises AND writing your own functions that leverage promises to provide clean abstractions and error handling.
Installation & Update
There are two ways to run the workshop:
Create a new directory to do your workshop work in. Let's call it "promise-shop". You will need to initialize npm in this repo.
$ mkdir promise-shop && cd promise-shop $ npm init $ npm install -g promise-it-wont-hurt@latest
Note: the workshop is being updated weekly. Please regularly rerun the above command to get the latest set of exercises.
Note for beginners: Do not do this if you do not have docker installed.
alias promise-it-wont-hurt='docker run -it -v $(pwd):/root oreng/promises-workshop' promise-it-wont-hurt # show menu promise-it-wont-hurt run mysolution.js # run your solution promise-it-wont-hurt verify mysolution.js # verify your solution
The workshop stores your progress in .config so
sudo rm -r .config will
reset the workshop!
1. Selecting a problem to work on
Once the workshop is installed, run
promise-it-wont-hurt to print a menu
where you can select a problem to work on.
Problems are listed in rough order of difficulty. You are advised to complete them in order, as later problems will build on skills developed by solving previous problems.
2. Writing your solution
Once you have selected a problem, the workshop will remember which problem you are working on. Using your preferred editor, simply create a file to write your solution in.
3. Testing your solution
Use the workshop's
run command to point the workshop at your solution file. Your solution will loaded
and passed the problem input. This usually won't perform any validation, it will only show the program output.
$ promise-it-wont-hurt run mysolution.js
4. Verifying your solution
Your solution will be verified against the output of the 'official' solution. If all of the output matches, then you have successfully solved the problem!
$ promise-it-wont-hurt verify mysolution.js
Feedback and criticism is welcome, please log your troubles in issues.
This tutorial was built using rvagg's workshopper framework.