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JavaScript: Return true if a value is an empty object, collection, map or set, has no enumerable properties or is any type that is not considered a collection

JavaScript fundamental (ES6 Syntax): Exercise-200 with Solution

Write a JavaScript program that will return true if a value is an empty object, collection, map or set, has no enumerable properties or is any type that is not considered a collection.

  • Check if the provided value is null or if its length is equal to 0.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const isEmpty = val => val == null || !(Object.keys(val) || val).length;

console.log(isEmpty(new Map()));
console.log(isEmpty(new Set()));
console.log(isEmpty([]));
console.log(isEmpty({}));
console.log(isEmpty(''));
console.log(isEmpty([1, 2]));
console.log(isEmpty({ a: 1, b: 2 }));
console.log(isEmpty('text'));
console.log(isEmpty(123));
console.log(isEmpty(true));

Sample Output:

true
true
true
true
true
false
false
false
true
true

Flowchart:

flowchart: Return true if a value is an empty object, collection, map or set, has no enumerable properties or is any type that is not considered a collection.

Live Demo:

See the Pen javascript-basic-exercise-200-1 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv