Why is my code returning the wrong value?

Asked Feb 24 '19 at 14:38

Active Feb 24 '19 at 14:45

Viewed 126 times

can anyone tell my why this happens?

checkSessionToken() {
    var sessionToken = loginCookies.get("sessionToken");

    if (typeof sessionToken !== "undefined") {
        var callback = "a";
        axios
            .get(backendServerURL + "/login.php", {
                params: {
                    action: "checkSessionToken",
                    token: sessionToken
                }
            })
            .then(res => {
                callback = "b";
                console.log("---");
            });
        return callback;
    } else {
        return false;
    }
}

render() {
    console.log(this.checkSessionToken());
}

the function is always returning "a" ... but I see the "---" in the console so it should be "b" does anyone of you know why this happens .... sorry for might beeing a noob I'm new to js

EDIT: when I say

return "b";

in the

.then(res => {});

so it would be

.then(res => {
    return "b";
});

it returns undefined

edited Feb 24 '19 at 14:41

asked Feb 24 '19 at 14:38

Gianluca Filitz

1

callback gets set later as its async – Lawrence Cherone Feb 24 '19 at 14:39
The function you pass into `.then()` is only invoked when the `.get()` call completes. The call to `.then()` however returns *immediately*. JavaScript programming involves dealing with asynchronous APIs pretty much all the time. – Pointy Feb 24 '19 at 14:41
sounds good but how can i return a async var? – Gianluca Filitz Feb 24 '19 at 14:41
*You cannot do that.* You can return a Promise and use another `.then()` call to handle the `.get()` results. – Pointy Feb 24 '19 at 14:42
can also just remove .then from inside the scope and `return axios.`, then do it outside `checkSessionToken.then()` also instead of return false you would want return Promise.reject() – Lawrence Cherone Feb 24 '19 at 14:45
thanks guys ... for everyone whos looking here ... the awnser is in the duplicate questions – Gianluca Filitz Feb 24 '19 at 15:02

Why is my code returning the wrong value?

0 Answers0