JSON.stringify()

Converts JS object or value to a JSON string

JSON.stringify({ x: 5, y: 6 }); // "{"x":5,"y":6}"
JSON.stringify({}) // '{}' 
JSON.stringify(true) // 'true' 
JSON.stringify('foo') // '"foo"' 
JSON.stringify([1, 'false', false]) // '[1,"false",false]' 
JSON.stringify([NaN, null, Infinity]) // '[null,null,null]' 
JSON.stringify({ x: 5 }) // '{"x":5}'
JSON.stringify(new Date(2006, 0, 2, 15, 4, 5)) // '"2006-01-02T15:04:05.000Z"'

Can stringify array of objects

JSON.stringify(
  [
    new Number(3), 
    new String('false'), 
    new Boolean(false)
  ]
); // "[3,"false",false]"

Some data types will be forced to null when stringified

JSON.stringify(
  {
    x: [10, undefined, function(){}, Symbol('')] 
  }
); // "{"x":[10,null,null,null]}"

Functions are not serializable

Function has two parts:

• body
• context/environment it is called in

When your function is serialized, it loses the context/environment after it is de-serialized and called.

var someValue = "something";

var obj = {
 propertyName: "A value",
 functionName: function(){
  // do something with someValue variable
  // after being deserialized, funciton will not know about `someValue`
 }
}

JSON.parse()

Method to construct the JavaScript value or object described by the string.

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json);

console.log(obj.count);
// Expected output: 42

console.log(obj.result);
// Expected output: true