JavaScript : Create an object composed of the properties the given function returns truthy for

JavaScript fundamental (ES6 Syntax): Exercise-97 with Solution

Write a JavaScript program to create an object composed of the properties the given function returns truthy for. The function is invoked with two arguments: (value, key).

• Use Object.keys(obj) and Array.prototype.filter()to remove the keys for which fn returns a falsy value.
• Use Array.prototype.reduce() to convert the filtered keys back to an object with the corresponding key-value pairs.
• The callback function is invoked with two arguments: (value, key).

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const pickBy = (obj, fn) =>
  Object.keys(obj)
    .filter(k => fn(obj[k], k))
    .reduce((acc, key) => ((acc[key] = obj[key]), acc), {});
console.log(pickBy({ a: 1, b: '2', c: 3 }, x => typeof x === 'number'));

Sample Output:

{"a":1,"c":3}

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-97-1 by w3resource (@w3resource) on CodePen.

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