JavaScript How to Convert Object to JSON String

Use JSON.stringify(yourObject) to convert a JavaScript object into a JSON string.

Examples

Input{"name":"Alice"}

Output"{\"name\":\"Alice\"}"

Input{"age":30,"city":"New York"}

Output"{\"age\":30,\"city\":\"New York\"}"

Input{}

Output"{}"

How to Think About It

To convert an object to a JSON string, think of turning the object's data into a text format that can be saved or sent. JavaScript provides a built-in tool called JSON.stringify that takes the object and returns its string form.

Algorithm

1

Get the JavaScript object you want to convert.

2

Use the <code>JSON.stringify</code> function with the object as input.

3

Receive the JSON string output representing the object.

Code

javascript

const obj = { name: "Alice", age: 30 };
const jsonString = JSON.stringify(obj);
console.log(jsonString);

Output

{"name":"Alice","age":30}

Dry Run

Let's trace converting { name: "Alice", age: 30 } to a JSON string.

1

Start with object

{ name: "Alice", age: 30 }

2

Apply JSON.stringify

JSON.stringify({ name: "Alice", age: 30 })

3

Get JSON string

"{\"name\":\"Alice\",\"age\":30}"

Step	Action	Value
1	Input object	{ name: "Alice", age: 30 }
2	Convert with JSON.stringify	"{\"name\":\"Alice\",\"age\":30}"

Why This Works

Step 1: What JSON.stringify does

JSON.stringify takes an object and turns it into a string that looks like JSON format.

Step 2: Why convert to string

Strings can be saved to files, sent over the internet, or logged, unlike objects.

Step 3: Result format

The output string uses quotes and braces to represent the object structure in text form.

Alternative Approaches

Manual string building

javascript

const obj = { name: "Alice", age: 30 };
const jsonString = '{"name":"' + obj.name + '","age":' + obj.age + '}';
console.log(jsonString);

This works only for simple objects and is error-prone; not recommended for complex objects.

Using a library like Lodash (for deep cloning and then stringify)

javascript

import _ from 'lodash';
const obj = { name: "Alice", age: 30 };
const cloned = _.cloneDeep(obj);
const jsonString = JSON.stringify(cloned);
console.log(jsonString);

Useful if you want to safely clone before converting, but adds dependency and complexity.

Complexity: O(n) time, O(n) space

Time Complexity

JSON.stringify processes each property in the object once, so time grows linearly with object size.

Space Complexity

The output string size depends on the object size, so space used is proportional to input size.

Which Approach is Fastest?

JSON.stringify is optimized and fastest for converting objects to JSON strings compared to manual methods.

Approach	Time	Space	Best For
JSON.stringify	O(n)	O(n)	All object sizes, reliable conversion
Manual string building	O(n)	O(n)	Very simple objects, not recommended
Using Lodash cloneDeep + stringify	O(n)	O(n)	When cloning needed before conversion