Maps the values of an array to an object using a function, where the key-value pairs consist of the original value as the key and the mapped value.
Use an anonymous inner function scope to declare an undefined memory space, using closures to store a return value. Use a new Array to store the array with a map of the function over its data set and a comma operator to return a second step, without needing to move from one context to another (due to closures and order of operations).
const mapObject = (arr, fn) => +
Maps the values of an array to an object using a function, where the key-value pairs consist of the stringified value as the key and the mapped value.
Use an anonymous inner function scope to declare an undefined memory space, using closures to store a return value. Use a new Array to store the array with a map of the function over its data set and a comma operator to return a second step, without needing to move from one context to another (due to closures and order of operations).
const mapObject = (arr, fn) => (a => ( (a = [arr, arr.map(fn)]), a[0].reduce((acc, val, ind) => ((acc[val] = a[1][ind]), acc), {}) ))(); diff --git a/snippets/checkProp.md b/snippets/checkProp.md index 41e26c9e8..4644eb666 100644 --- a/snippets/checkProp.md +++ b/snippets/checkProp.md @@ -14,6 +14,7 @@ const checkProp = (predicate, prop) => obj => !!predicate(obj[prop]); + const lengthIs4 = checkProp(l => l === 4, 'length'); lengthIs4([]); // false lengthIs4([1,2,3,4]); // true