anirudh-eka’s gists

anirudh-eka / exploring-fold-composition.js

Created June 13, 2022 16:59

Basically exploring 1. composing reducer functions 2. classic list fold, an early termination list fold, and a iterator fold.

	// composeFolds :: [(a, x) -> (a \| null)] -> ((a, x) -> (a \| null))
	//
	// `composeFolds` composes reducer functions from left-to-right.
	// For example, composeFolds(sum, take(10)) will first call `sum`,
	// then `take(10)`. On each iteration of a fold, each reducer receieves
	// the aggregate, and the new value (`x`), and returns a new aggregator
	// that gets passed along to the next reducer, along with `x`.
	//
	function composeFolds(...fs) {
	return fs.reduce((g, f) => (a, x) => {

anirudh-eka / range-with-lazy-foreach.js

Created June 11, 2022 06:13

	// An implementation of a range construction with a lazily evaluated forEach

	// Usage:
	range(1,5).forEachLazy(console.log) //prints 1, 2, 3, 4, 5
	range(1).forEachLazy(console.log) //prints 1, 2... forever


	function range(from, to=Infinity) {
	const gen = __range(from, to)
	gen.forEachLazy = __forEachLazy(gen)

anirudh-eka / functionSpread.js

Last active June 11, 2022 06:06

	// Function Spread
	// https://medium.com/@anirudheka/how-to-use-the-spread-operator-on-a-function-b7dd9d13752a?sk=b85ebf2107d618184ad4e44a2270835f

	const spread = (...fns) =>
	fns.reduce((a, f) => x => {
	const v = f(x)
	return v !== undefined ? v : a(x)
	})

	// usage

anirudh-eka / transducerBlogExtractReducersExtractFilterAndMapLogic.js

Last active August 6, 2018 07:44

	const mapping = mapLogic => reducer => (a, x) => {
	const transformed = mapLogic(x);
	return reducer(a, transformed)
	}

	const filtering = filterLogic => reducer => (a, x) => {
	if(filterLogic(x)) {
	return reducer(a, x)
	} else {
	return a;

anirudh-eka / transducerBlogExtractReducersPassNextReducer.js

Last active August 6, 2018 07:40

	const mapAdd1Transducer = reducer => (a, x) => {
	const transformed = x + 1;
	return reducer(a, transformed)
	}
	const filterGreaterThan2Transducer = reducer => (a, x) => {
	if(x > 2) {
	return reducer(a, x)
	} else {
	return a;
	}

anirudh-eka / transducerBlogExtractReducersPassNextReducerToFilter.js

Last active August 5, 2018 16:15

	const mapAdd1Reducer = (a, x) => {
	const transformed = x + 1;
	return a.concat(transformed)
	}

	const filterGreaterThan2Transducer = reducer => (a, x) => {
	if(x > 2) {
	return reducer(a, x)
	} else {
	return a;

anirudh-eka / transducerBlogExtractReducersWithChain.js

Created August 5, 2018 15:56

	const filterGreaterThan2AndMapAdd1Reducer = (a, x) => {
	if(x > 2) {
	return mapAdd1Reducer(a, x)
	} else {
	return a;
	}
	}

	[1, 2, 3].reduce(filterGreaterThan2AndMapAdd1Reducer, []);

anirudh-eka / transducerBlogExtractReducers.js

Created August 5, 2018 15:50

	const mapAdd1Reducer = (a, x) => {
	const transformed = x + 1;
	return a.concat(transformed)
	}
	const filterGreaterThan2Reducer = (a, x) => {
	if(x > 2) {
	return a.concat(x)
	} else {
	return a;
	}

anirudh-eka / mappingOverJayZDetailsFunction.js

Created June 18, 2018 15:06

	const jayZDetailsFn = (k) => jayZDetails[k];

	const intermediateResult = mapFn(stringifyNumber, jayZDetailsFn);
	//=> x => stringifyNumber(jayZDetailsFn(x))

	const result = mapFn(addAgeSuffix,intermediateResult);
	//=> x => addAgeSuffix(stringifyNumber(jayZDetailsFn(x)))

	result('demeanorAge') //=> 'seventy eight years old';

anirudh-eka / mappingOverJayZDetailsObject.js

Last active June 18, 2018 15:23

	const jayZDetails = { age: 48, demeanorAge: 78 };

	const intermediateResult = mapObj(stringifyNumber, jayZDetails);
	// => { age: 'forty eight', demeanorAge: 'seventy eight' }

	const finalResult = mapObj(addAgeSuffix, intermediateResult));
	// => { age: 'forty eight years old', demeanorAge: 'seventy eight years old' }

	result['demeanorAge'] //=> 'seventy eight years old';