JavaScript JSON.stringify() Example

The JSON.stringify() method converts a JavaScript object or value to a JSON string, optionally replacing values if a replacer function is specified or optionally including only the specified properties if a replacer array is specified.

JavaScript JSON.stringify() Example

Example 1: Let's create a Javascript object:
  var user = {
    firstName : 'Ramesh',
    lastName : 'Fadatare',
    emailId : 'ramesh@gmail.com',
    age : 29
  }
Convert above Javascript object into JSON string as:
JSON.stringify(user)
console.log(JSON.stringify(user));
Output:
{"firstName":"Ramesh","lastName":"Fadatare","emailId":"ramesh@gmail.com","age":29}
Example 2: replacer argument example, as a function
function replacer(key, value) {
  // Filtering out properties
  if (typeof value === 'string') {
    return undefined;
  }
  return value;
}

var foo = {foundation: 'Mozilla', model: 'box', week: 45, transport: 'car', month: 7};
JSON.stringify(foo, replacer);
Output:
"{"week":45,"month":7}"
Example 3: replacer argument example, as an array
If replacer is an array, the array's values indicate the names of the properties in the object that should be included in the resulting JSON string.
var foo = {foundation: 'Mozilla', model: 'box', week: 45, transport: 'car', month: 7};
JSON.stringify(foo, ['week', 'month']);  
Output:
"{"week":45,"month":7}"
Example 4: The space argument example. The space argument may be used to control spacing in the final string.
JSON.stringify({ a: 2 }, null, ' ');
Output:
"{
 "a": 2
}"
Using a tab character mimics standard pretty-print appearance:
JSON.stringify({ uno: 1, dos: 2 }, null, '\t');
Output:
"{
 "uno": 1,
 "dos": 2
}

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