JavaScript JSON Serializing and restoring class instances
Example
You can use a custom toJSON method and reviver function to transmit instances of your own class in JSON. If an object has a toJSON method, its result will be serialized instead of the object itself.
6
function Car(color, speed) {
this.color = color;
this.speed = speed;
}
Car.prototype.toJSON = function() {
return {
$type: 'com.example.Car',
color: this.color,
speed: this.speed
};
};
Car.fromJSON = function(data) {
return new Car(data.color, data.speed);
};
6
class Car {
constructor(color, speed) {
this.color = color;
this.speed = speed;
this.id_ = Math.random();
}
toJSON() {
return {
$type: 'com.example.Car',
color: this.color,
speed: this.speed
};
}
static fromJSON(data) {
return new Car(data.color, data.speed);
}
}
var userJson = JSON.stringify({
name: "John",
car: new Car('red', 'fast')
});
This produces the a string with the following content:
{"name":"John","car":{"$type":"com.example.Car","color":"red","speed":"fast"}}
var userObject = JSON.parse(userJson, function reviver(key, value) {
return (value && value.$type === 'com.example.Car') ? Car.fromJSON(value) : value;
});
This produces the following object:
{
name: "John",
car: Car {
color: "red",
speed: "fast",
id_: 0.19349242527065402
}
}
