How to Check If a Value is an Object in JavaScript

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To check if a value is an Object in JavaScript, you can use the “typeof” operator, “instanceof” operator, or “Object.prototype.toString.call()” function.

Method 1: Using the typeof operator

The “typeof operator” returns a string representing the value type. To check if a value is an Object, you can compare the result of typeof with the string “Object”. However, this method considers null an Object, so you must add a check to exclude null values.

Example

function isObject(value) {
  return value !== null && typeof value === 'object';
}

const objectValue = { key: 'value' };
const nullValue = null;
const stringValue = 'hello';

console.log(isObject(objectValue));
console.log(isObject(nullValue));
console.log(isObject(stringValue));

Output

true
false
false

Method 2: Using the instanceof operator

The “instanceof operator” checks if a value is an instance of the specific class or constructor. For example, you can use instanceof with the Object constructor to check if a value is an object. However, like the typeof operator, this method considers null an Object, so you must add a check to exclude null values.

Example

function isObject(value) {
  return value !== null && value instanceof Object;
}

const objectValue = { key: 'value' };
const nullValue = null;
const stringValue = 'hello';

console.log(isObject(objectValue));
console.log(isObject(nullValue));
console.log(isObject(stringValue));

Output

true
false
false

Method 3: Using the Object.prototype.toString.call() function

The Object.prototype.toString.call() function returns a string representing the value type. Unlike the typeof operator and the instanceof operator, this method does not consider null an Object. You can use this method to check if a value is an object by comparing the result with the string ‘[object Object]’.

Example

function isObject(value) {
  return Object.prototype.toString.call(value) === '[object Object]';
}

const objectValue = { key: 'value' };
const nullValue = null;
const stringValue = 'hello';

console.log(isObject(objectValue));
console.log(isObject(nullValue));
console.log(isObject(stringValue));

Output

true
false
false

Each method has pros and cons, so choose the one that best suits your needs based on their behavior and compatibility with your specific use case.

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