Scaling
Best practices With Syntax Trees

Will Klein

Best Practices

Knowledge

How do I code here

Testing

User

Experience

 

Developer

Experience

 

Documentation

Brown Bags

Code review

Convention Tests

Convention Tests, AKA

• Linters
• Code analyzers
• Static analysis

Language

Conventions

What about     our project Conventions?

What about     our Framework Conventions?

What If We could write our own convention tests?

Convention Test "Frameworks"

• Common tests included
• Pluggable testing API
• ESLint, for example

// Life, Universe, and Everything
var answer = 6 * 7;

// Life, Universe, and Everything
var answer = 6 * 7;

10111010001011011101000101

...

How does this work?

// Life, Universe, and Everything
var answer = 6 * 7;

[var] [answer] [=] [6] [*] [7][;]

...

Tokenize

// Life, Universe, and Everything
var answer = 6 * 7;

[var] [answer] [=] [6] [*] [7][;]

...

...

?

Parse

A Syntax Tree

Syntax Tree

• Abstract syntax tree
• AST
• Syntax tree is easier to say

ESLint

• Builds our syntax tree for us
• Iterates over nodes in the tree
• For each node, do we have a test?

ESLint: Rule boilerplate

ESLint: Rule boilerplate

ESLint: Rule boilerplate

ESLint: Rule boilerplate

Demo

github.com/willklein/scaling-best-practices

Docs & Code

Go Forth and Test

• Implement existing tools
• Consider your project's conventions
• Write your own convention tests

Go Forth and Test

• Implement existing tools
• Consider your project's conventions
• Write your own convention tests
• Improve your developer experience

programs must be written for people to read, and only incidentally for machines to execute

Donald Knuth

Structure and Interpretation of Computer Programs

http://willkle.in

will.klein@gmail.com

Thanks

@willslab