Why when I dont use intermediate variable this function doesn't work?

Question

Here's my function:

function Ship(shipType) {

    this.name = shipType;
    this.detailedName = function() {
        var c=
            this.name.charAt(0).toUpperCase() +
            this.name.slice(1);
        return c;
    };
}

Now if I try to optimize = without intermediate variable, this doesn't work. Why?

function Ship(shipType) {

    this.name = shipType;
    this.detailedName = function() {
        return
            this.name.charAt(0).toUpperCase() +
            this.name.slice(1);
    };
}

Here's the fiddle that shows the problem: http://jsfiddle.net/VW5w3/

Answer 1

Automatic Semicolon Insertion. The browser tries to correct your return to a return;.

If you put the return value into the same line as the return keyword, it will work correctly, have a look at this updated fiddle: http://jsfiddle.net/VW5w3/1/

return this.name.charAt(0).toUpperCase() + this.name.slice(1);

Answer 2

I believe it is because ; is not mandatory in JS, so return returns undefined. Write return in one line instead: return this.name.charAt(0).toUpperCase() + this.name.slice(1);