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javascriptecmascript-5

Why does Chrome & FireFox console print 'undefined'?

Take this simple Test object and paste it into the console. You'll see that it says undefined. The object is working because it also prints 123, but what is the undefined about?

Test:

var Test = new (function(){
    return {
        get testing(){
            return "123";
        }
    }
});

console.log(Test.testing);

Console Output:

123
undefined
Solution

  • That is the return value of console.log.

    Try

    console.log(1);

    which gives

    1
undefined

    However, if you type just

    Test.testing

    that gives only

    "123"