Find the length of a JavaScript object
Finding the length of a JavaScript object involves determining the number of properties or keys it contains. This is essential for assessing the size or complexity of the object, aiding in data analysis, and facilitating efficient object manipulation in JavaScript applications.
Below are the following approaches:
Table of Content
- Method 1: Using the Object.keys() method
- Method 2: Using for-in loop and hasOwnProperty() Method
- Method 3: Using Object.entries() Method
- Method 4: Using Lodash _.size() Method
- Method 5: Using the for…of loop with Object.values() Method
Method 1: Using the Object.keys() method
The Object.keys() method is used to return the object property name as an array. The length property is used to get the number of keys present in the object. It gives the length of the object.
Syntax:
objectLength = Object.keys(exampleObject).length
Example: This example shows the use of the above-explained approach.
function getObjectLength() {
// Declare an object
exampleObject = {
id: 1,
name: 'Arun',
age: 30
}
// Using Object.keys() method to get length
objectLength = Object.keys(exampleObject).length;
console.log(objectLength);
}
getObjectLength();
Output
3
Method 2: Using for-in loop and hasOwnProperty() Method
The hasOwnProperty() method is used to return a boolean value indicating whether the object has the specified property as its property. This method can be used to check if each key is present in the object itself. The contents of the object are looped through and if the key is present, the total count of keys is incremented. This gives the length of the object.
Syntax:
let key, count = 0;
// Check if every key has its own property
for (key in exampleObject) {
if (exampleObject.hasOwnProperty(key))
// If the key is found, add it to the total length
count++;
}
objectLenght = count;
Example: This example shows the use of the above-explained approach.
function getObjectLength() {
// Declare an object
exampleObject = {
id: 1,
name: 'Arun',
age: 30,
department: 'sales'
}
let key, count = 0;
// Check if every key has its own property
for (key in exampleObject) {
if (exampleObject.hasOwnProperty(key))
// If key is found, add it
// to total length
count++;
}
objectLength = count;
console.log(objectLength);
}
getObjectLength();
Output
4
Method 3: Using Object.entries() Method
JavaScript Object.entries() method is used to return an array consisting of enumerable property [key, value] pairs of the object which are passed as the parameter. The ordering of the properties is the same as that given by looping over the property values of the object manually.
Syntax:
Object.entries(obj)
Example: This example shows the use of the above-explained approach.
function getObjectLength() {
// Declare an object
exampleObject = {
id: 1,
name: 'Arun',
age: 30,
department: 'sales'
}
const objectLength = Object.entries(exampleObject).length;
console.log(objectLength);
}
getObjectLength();
Output
4
Method 4: Using Lodash _.size() Method
Lodash _.size() method is used to get the size of the given object or array.
Example: This example shows the use of the above-explained approach.
// Requiring the lodash library
const _ = require("lodash");
// Original array and use _.size() method
let gfg = _.size({ 'p': 1, 'q': 2, 'r': 5 });
// Printing the output
console.log(gfg);
Output:
3
Method 5: Using the for…of loop with Object.values() Method
The for…of loop combined with the Object.values() method provides a concise way to iterate over the property values of an object. By iterating over the values and counting them, we can determine the length of the object.
Syntax:
let count = 0;
// Iterate over the values of the object
for (const value of Object.values(exampleObject)) {
// Increment the count for each value encountered
count++;
}
objectLength = count;
Example:
const exampleObject = { a: 1, b: 2, c: 3 };
let count = 0;
for (const value of Object.values(exampleObject)) {
count++;
}
console.log(count); // Output: 3
Output
3
JavaScript is best known for web page development but it is also used in a variety of non-browser environments. You can learn JavaScript from the ground up by following this JavaScript Tutorial and JavaScript Examples.
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