Javascript - smartest solution for many conditions-CodePudding

In javascript I have a function, where I have too many conditions. I wonder what will be the smartest solution to rework this function.

Currently I have it like this. Of course there are more than 20 conditions, just for example I have 3 here:

function checkURL(pageName) (
let urlPart = '';
if (pageName == 'something') { urlPart = "main/contact";}
if (pageName == 'anythingelse') { urlPart = "administration/user";}
if (pageName == 'another page') { urlPart = "administration/country";}

return urlPart;
)

I was thinking to rework it with switch/case or put the pageName variable into array and urlPart as well, and then just find the pageName position in array and compare with urlPart position, e.g.:

    function checkURL(pageName) (
const pg = ["something", "anythingelse", "another page"];
const url = ["main/contact", "administration/user", "administration/country"];

let index1 = pg.indexOf(pageName);
if (index1>=0) {return url[index1];} else {return ''; }
)

The problem might be with matching the same position of both elements in array, as people will add more and more items to the array and they can do a mistake where the position in first array will not match the correct position in second array when we will have 50 items maybe.

CodePudding user response：

You don't need to use checks at all for this.

Simply create an object that is used as a kind of lookup table. So in the case of your code, something like this:

const urls = {
  "something": "main/contact",
  "anythingelse": "administration/user",
  "another page": "administration/country"
}

Now you don't need to run a bunch of checks, but a single check (that the urls object has a key that matches pageName). If that check succeeds, return the result. Otherwise, return a default / error page.

function checkURL(pageName) (
  return urls[pageName] || "main/pageNotFound";
)

CodePudding user response：

load the settings from a json file, like this:

const jsonText = `{
  "pages": {
    "something": "main/contact",
    "anythingelse": "administration/user"
  }
}`;
let pages = JSON.parse(jsonText).pages;

console.log('pages["something"]:', pages['something']);
console.log('pages["anythingelse"]:', pages['anythingelse']);
console.log('pages["not_found"]:', pages['not_found']);