JavaScript: Get a list of elements that exist in both arrays, after applying the provided function to each array element of both

JavaScript fundamental (ES6 Syntax): Exercise-210 with Solution

Write a JavaScript program to get a list of elements in both arrays, after applying the provided function to each array element of both.

• Use Array.prototype.filter() and Array.prototype.findIndex() in combination with the provided comparator to determine intersecting values

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const intersectionBy = (a, b, fn) => {
  const s = new Set(b.map(x => fn(x)));
  return a.filter(x => s.has(fn(x)));
};

console.log(intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor));

Sample Output:

[2.1]

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-210-1 by w3resource (@w3resource) on CodePen.

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