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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