Conditional logic in the constructor using Javascript may or may not include if

Question

Conditional logic in the constructor using Javascript may or may not include if

Check out this starting code snippet.

function person(name, age, child){
    this.name = name;
    this.age = age;
    if(this.child == undefined){
        this.child = 'default';
    }else{
        this.child = child;
    }
}
var sarah = new person('sarah',34,true);

document.write(sarah.child+' ');

I'm attempting to include an optional property in a constructor function. However, regardless of what I provide as the value for the child parameter, it always displays 'default' when outputted. I am relatively new to JS, coming from a background in PHP. I can't figure out why this isn't working. I've researched other similar issues and tried various solutions, but nothing seems to fix the problem.

javascript

Answer 1

Answer №1

Have you considered using child = child || 'default' in place of a traditional if-else statement?

It accomplishes the same result with less code.

Answer 2

Have you considered using child = child || 'default' in place of a traditional if-else statement?

It accomplishes the same result with less code.

Answer 3

Answer №2

Here is the corrected code snippet:

function person(name, age, child){
    this.name = name;
    this.age = age;
    if(child == undefined){
        this.child = 'default';
    }else{
        this.child = child;
    }
}
var sarah = new person('sarah',34,true);

document.write(sarah.child+' '); // true

The issue here is that the comparison should be made with the argument child instead of this.child.

A more concise solution would be to use a ternary operator:

this.child = child || 'default';

Answer 4

Here is the corrected code snippet:

function person(name, age, child){
    this.name = name;
    this.age = age;
    if(child == undefined){
        this.child = 'default';
    }else{
        this.child = child;
    }
}
var sarah = new person('sarah',34,true);

document.write(sarah.child+' '); // true

The issue here is that the comparison should be made with the argument child instead of this.child.

A more concise solution would be to use a ternary operator:

this.child = child || 'default';

Conditional logic in the constructor using Javascript may or may not include if

Answer №1

Answer №2

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