Why is this javascript function returning undefined?

Question

Why is this function returning undefined? It has a value inside the function, but once I try to assign it to a new variable, it comes back as undefined.

function getLookupDefault(lookupModel) {
    Object.keys(lookupModel.LookupValues).forEach(function (key) {
        if (lookupModel.LookupValues[key].IsDefault == true) {
            test = lookupModel.LookupValues[key].Name;
            console.log("test: " + test);
            return test;
        }
    })
};

var tst = getLookupDefault(model.LookupValuesDelimiter);
console.log("tst: " + tst);

Edit: Thank you. Coming from c#, this was not obvious to me. I have edited the code to this and it works correctly.

function getLookupDefault(lookupModel) {
    for (var key in Object.keys(lookupModel.LookupValues)) {
        if (lookupModel.LookupValues[key].IsDefault == true) {
            test = lookupModel.LookupValues[key].Name;
            console.log("test: " + test);
            return test;
        }
    }
}

because it has no return statement in it - you also "return" in a .forEach callback, which is pointless, ... perhaps you wanted `map` instead — Jaromanda X, Mar 08 '18 at 05:14
oh for goodness sake, remove the image, it adds nothing to the question — Jaromanda X, Mar 08 '18 at 05:16
@ScottMarcus - yes, well spotted, but where is there a return in the `getLookupDefault` function? and returning a value from a forEach callback does nothing anyway — Jaromanda X, Mar 08 '18 at 05:17
@ScottMarcus He uses it on the `forEach` block which is useless. — wisn, Mar 08 '18 at 05:17
@JaromandaX You edited your comment. Your original comment made it seem like you didn't see any `return` in the code. — Scott Marcus, Mar 08 '18 at 05:17
the edit does not change the first part of that comment ... `getLookupDefault` still has no return statement in it — Jaromanda X, Mar 08 '18 at 05:18
I don't know if either of those duplicates is actually what OP is trying to do here. I think they're actually looking for a way to break out of a `forEach` loop with a `return` like you can do with a normal `for` loop in most languages. — SCB, Mar 08 '18 at 05:22
If that is the case, [this answer here](https://stackoverflow.com/a/32101207/1112586) might be more like what they're looking for. — SCB, Mar 08 '18 at 05:26

score 1 · Accepted Answer · answered Mar 08 '18 at 05:16

1

That return statement you have in there doesn't return a value to the outer function, it only returns a value to the inner function called by forEach.

answered Mar 08 '18 at 05:16

kshetline

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i.e. it's a star trek GNDN ... goes nowhere, does nothing – Jaromanda X Mar 08 '18 at 05:17

Why is this javascript function returning undefined?

1 Answers1