Javascript - function with optional parameters as object?

Question

I need a function that its parameter is an object, and if I leave it empty it will load default values.

something like:

function loadMap(args) { //args is an object and its optional

   //this is what I want to do, test args and load defauts if necesary
   /*
   pseudocode:
   if args.latitude is not set then
       give it a default value

   if args.longitude is not set then
       give it a default value

    end pseudocode */

   alert("Latitude is "+args.latitude );
   alert("Longitude is "+args.longitude );
}

//outputs the default values
loadMap();

//outputs custom values
loadMap({latitude: "x.xxxx", longitude: "-x.xxxx"});

//and should work too and output one default and one custom value
loadMap({latitude: "x.xxxx"});

I found this solution in this question (Is there a better way to do optional function parameters in Javascript?) but it requires jQuery: http://jsfiddle.net/xy84kwdv/

It's ALMOST what I want but I don't want to depend on a jquery function.

Answer 1

Surely this question is over 3 years old now(2018-03-02). I searched about this topic but most of the questions I got and the answers ranked top are seemed like to be outdated, like this, this, this, or this.

Currently, lots of browsers support ES6/ECMAScript 2015(the 6th Edition of ECMAScript). For compatibility, you can use WebpackJs(or another packer) and BabelJs(or another compiler) to compile and pack your ES6 codes to ES5. And the ES6-version answer for this question may be Object Destructuring.

function drawES2015Chart({size = 'big', cords = {x: 0, y: 0}, radius = 25} = {}) {
    console.log(size, cords, radius);
    // do some chart drawing
}

drawES2015Chart({cords: {x: 18, y: 30}, radius: 30});

function fn(requiredArg, {optionalArg = 'Default Value', a = 1, b ={some: 'object'}} = {}){
    // Do with destructured values: requiredArg, optionalArg, a, and b.
    console.log(requiredArg, optionalArg, a, b);
}

so for your question, it will be:

function loadMap({latitude = "x.xxxx", longitude = "-x.xxxx"} = {}) {
    console.log('latitude is:', latitude, 'and longitude is:', longitude);
    console.log(`latitude is: ${latitude}, and longitude is: ${longitude}`);
}

// Call the function.
loadMap({latitude: "1.2345", longitude: "-6.7890"});