JSON serializing an object with function parameter

Question

I have this C# object:

var obj = new {
    username = \"andrey\",
    callback = \"function(self) { return function() {self.doSomething()} (this) }\"
}
         


        

Answer 1

You can make use of the constructor of the Function object. See https://developer.mozilla.org/nl/docs/Web/JavaScript/Reference/Global_Objects/Function.

In your json you set the callback property to a string array that describes the Function constructor parameters. Then when the json data has arrived on the client you have to convert the Array to an instance of the Function object.

This way you can have the function implementation details in your back database instead of hardcoded in source code.

const json = '{"username":"andrey","callback":["self","return self.doSomething()"]}';

//Parse the json to an object
const object = JSON.parse(json);

//Convert the callback property from Array to Function
object["callback"] = new Function(...object["callback"]);

//Create a parameter for calling the Function
var self = {
    doSomething() {
        console.log("Do something called");
    }
}

//Call the function
object["callback"](self);