Jethro Larson jethrolarson

Type Signatures for your JS

A form of documentation that helps developers understand what a function does.

// toUpper :: String -> String
const toUpper = str => str.toUpperCase()

Flyd

https://github.com/paldepind/flyd
License: MIT
Size: 22.4 KB (3.4 KB gzip)
Functions: 16
Project Life: Good
Stars: 1129
Code Quality: Good Functional/Procedural
Comments: JSDoc
Quality Automation: Extensive unit tests, CI

Note: These aren't necessarily mutually exclusive. E.g. we may want to use promise with thunk to get better ergonomics for certain kinds of effects.

Thunk

Learnability: 4
Testability: 4
Happy path: 4
Purity: 2
SLOC: 14

Doesn't do a lot for you. Just makes it easy to do async actions

	// Immutable update techniques

	// mutate in place
	myData.x.y.z = 7;
	myData.a.b.push(9);
	mydata.a.b[2] = 3;

	// clone and mutate
	const newData = deepCopy(myData);
	newData.x.y.z = 7;

	O(1) - Trivial, we've done something almost exactly like this and it wont take long to complete at all
	O(log n) - Need to add a small capability then it's copy-pasta
	O(n) - Simple, It's like things we've done before. No refactoring or architectural changes needed.
	O(n^2) - Going to need to rework some things and watch out for regressions
	O(n!) - Major rework needed, lots of risk
	O(MG) - This is so complex or ill-defined that it may never complete

	Lenses
	======

	What is a lens?
	---------------
	pair of getter and setter that perform immutable updates on parameterized data structure

	e.g.
	```js

	moment(0) // epoc
	moment(undefined) // Now
	moment(null) // Invalid Date
	moment(false) // throw warning, Invalid date
	moment(void 0) // Now
	moment('') // Invlid Date
	moment([]) // Now
	moment({}) // Now

	// Take string and get words as an array. Valid split characters are `,` `.` `\s` `/` `\n`
	// words :: String -> [String]
	export const words = str =>
	(str ? str.split(/[\s\n.,/]+/) : []) // split on whitespace
	.filter(Boolean);