JavaScript: Map the values of an array to an object using a function

JavaScript: Exercise-82 with Solution

Write a JavaScript program to map array values to an object using a function. The key-value pairs consist of the original value as the key and the mapped value.

Note: 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).

• Use Array.prototype.reduce() to apply fn to each element in arr and combine the results into an object.
• Use el as the key for each property and the result of fn as the value.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const mapObject = (arr, fn) =>
  (a => (
    (a = [arr, arr.map(fn)]), a[0].reduce((acc, val, ind) => ((acc[val] = a[1][ind]), acc), {})
  ))();
const squareIt = arr => mapObject(arr, a => a * a);
console.log(squareIt([1, 2, 3])); 

Sample Output:

{"1":1,"2":4,"3":9}

Pictorial Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-82-1 by w3resource (@w3resource) on CodePen.

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