Provider'xx'必须从AngularJs中的$ get factory方法返回一个值

Question

I have written an angularjs factory as below

module.factory('LogService', function () {

    function log(msg) {
        console.log("Rahkaran:" + new Date() + "::" + msg);
    }

    return 
    {
        log: log
    };

});

But I kept getting this error

Provider 'LogService' must return a value from $get factory method

I googled about the error and I couldn't find any solution.

Coincidentally I changed the return statement to this

return{
    log: log
};

And error is gone!!

Is there any differences between having { in front of return or at the next line?

Answer 1

This is called Automatic semicolon insertion

The return statement is affected by automatic semicolon insertion (ASI). There is no line terminator ; between the return keyword and the expression allowed.

return
a + b;

// is transformed by ASI into

return; 
a + b;

So you must insert { in front of return and Not at the next line.

Reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/return

Answer 2

In your case there will be always a non-undefined value returned. But in other cases the issue might be also that you do return null or undefined value from the factory.