CODEWITHSUNDEEP
javascriptobjectif-statement
user1431398
user1431398

Reputation:

Javascript – use X amount of object variables in if statement

I'd like to make the following code more generic/page-independent so that I can use it for other projects too.

The code is checking if a certain value in the localCache exists and if the location.pathname has a certain string. If so, it should scroll to top etc.

Now it looks like this:

if (referrer == "home" && location.pathname == "projects"){
    window.scrollTo(0,0);
    localStorage.setItem('referrer', 'projects');
}

I'd like to make more generic so that it's not depending on the exact amount of strings of the location.pathname and so that it can refer to an X amount of location.pathnames.

I tried to make an object out of the different strings like this:

let object = {
    homePage: "home",
    noScrollPages: {[
      "projects", 
      "about",
      "info"
    ]}
}

if (referrer == homePage && (location.pathname == "/" + noScrollPages[0]) || location.pathname == "/" + noScrollPages[1] || location.pathname == "/" + noScrollPages[2]){
    window.scrollTo(0,0);
    localStorage.setItem("referrer", noScrollPages[0, 1, 2 or X, whichever resolves as true in the if statement]);
    console.log(localStorage.getItem("referrer"));
}

So, basically I don't know how code it so that it doesn't rely on the explicit declaration of [0] or [1], because it could be X number of pages.

Thanks for any tips!

Upvotes: 0

Views: 33

Answers (2)

ELinda
ELinda

Reputation: 2821

The previous solution works, but this is an alternative. If you have many different pages, it may be more efficient to use a Set, which comes with the has method, which allows you to check for existence of an element in constant time.

In this example, the location's pathname is "/projects", so locationName evaluates to "projects"; instead of checking each page for equality to the location's pathname when the page is prepended with a "/", we check for existence of a page equal to locationName (location without the initial slash).

let location  = {pathname: "/projects"} // setting this as test (REMOVE THIS)

let object = {
    homePage: "home",
    noScrollPages: new Set([
      "projects", 
      "about",
      "info"
    ])
}
let locationName = location.pathname.substring(1) // location without first slash

if (referrer == homePage && object.noScrollPages.has(locationName)){
    window.scrollTo(0,0);
    localStorage.setItem("referrer", locationName);
    console.log(localStorage.getItem("referrer"));
}

Upvotes: 1

joshwilsonvu
joshwilsonvu

Reputation: 2679

Try Array#find():

let object = {
    homePage: "home",
    noScrollPages: [
      "projects", 
      "about",
      "info"
    ]
}

// the matching page, or undefined if not found
const noScrollPage = object.noScrollPages.find(page => location.pathname === "/" + page);
if (referrer === homePage && noScrollPage) {
    window.scrollTo(0,0);
    localStorage.setItem("referrer", noScrollPage);
    console.log(localStorage.getItem("referrer"));
}

Upvotes: 1

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