Replace a value if null or undefined in JavaScript

Question

I have a requirement to apply the ?? C# operator to JavaScript and I don\'t know how. Consider this in C#:

int i?=null;
int j=i ?? 10;//j is now         


        

Answer 1

Here’s the JavaScript equivalent:

var i = null;
var j = i || 10; //j is now 10

Note that the logical operator || does not return a boolean value but the first value that can be converted to true.

Additionally use an array of objects instead of one single object:

var options = {
    filters: [
        {
            name: 'firstName',
            value: 'abc'
        }
    ]
};
var filter  = options.filters[0] || '';  // is {name:'firstName', value:'abc'}
var filter2 = options.filters[1] || '';  // is ''

That can be accessed by index.