Map Reduce Example

map1.js

const map = (fn, arr) => arr.reduce((acc, item) => {
	return acc.concat(fn(item));
}, []);

const myArray = [2, 4, 6, 8];
const reduceFn = item => item * 2;

const myReducer = map(reduceFn, myArray);

map2.js

(fn, arr) => arr.reduce((acc, item) => {
	return acc.concat(fn(item));
}, []);

map3.js

item => item * 2

map4.js

reduceFn
myArray

map5.js

[2].reduce(([], 2) => {
	return [].concat(2 * 2);
});

map6.js

[4].reduce(([4], 4) => {
	return [4].concat(4 * 2);
});

map7.js

[6].reduce([4, 8], 6) => {
	return [4, 8].concat(6 * 2);
});

map8.js

[8].reduce([4, 8, 12], 8) => {
	return [4, 8, 12].concat(8 * 2);
});

map9.js

[2, 4, 6, 8].map(item => item * 2);