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JavaScript: Check whether the provided value is an object created by the Object constructor

JavaScript fundamental (ES6 Syntax): Exercise-192 with Solution

Write a JavaScript program to check whether the provided value is an object created by the Object constructor.

  • Check if the provided value is truthy.
  • Use typeof to check if it is an object and Object.prototype.constructor to make sure the constructor is equal to Object.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const isPlainObject = val => !!val && typeof val === 'object' && val.constructor === Object;

console.log(isPlainObject({ a: 1 }));
console.log(isPlainObject(new Map()));

Sample Output:

true
false

Flowchart:

flowchart: Check whether the provided value is an object created by the Object constructor

Live Demo:

See the Pen javascript-basic-exercise-192-1 by w3resource (@w3resource) on CodePen.


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Next: Write a JavaScript program to check if a value is object-like. Check whether the provided value is not null and its typeof is equal to 'object'.

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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