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

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

Check If Object by Constructor

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:

// Define a function 'isPlainObject' that checks if the given value 'val' is a plain object
const isPlainObject = val =>
  // Check if 'val' is not falsy and is an object, and its constructor is Object
  !!val && typeof val === 'object' && val.constructor === Object;

// Test cases to check if the value is a plain object
console.log(isPlainObject({ a: 1 })); // true (the value is a plain object)
console.log(isPlainObject(new Map())); // false (the value is not a plain object)

Output:

true
false

Flowchart:

Live Demo:

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

For more Practice: Solve these Related Problems:

• Write a JavaScript program that verifies if a value is an object created by the Object constructor.
• Write a JavaScript function that tests whether an input is a plain object and not an instance of a custom class.
• Write a JavaScript program that uses Object.getPrototypeOf() to confirm that a value’s constructor is Object.
• Write a JavaScript function that distinguishes between plain objects and other object types using constructor checks.

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