Adding multiple Variables to check value of another variable, Javascript

Question

I am attemtping to add strings together to create the name of a variable, which I can then check its value. The code may explain this better, to understand what I mean. I have several variables like below

var scList = ["stream", "dev", "web"];

var stream_sc = ["test0", "test1"];
var dev_sc = ["value","value"];
var web_sc = ["value", "value"];

In another function I am checking if entered text matches one of the values in scList, I then hope to add the string "_sc" to the end of the entered text, and from there be able to display the values inside the variables ending in _sc. The below is what I have so far. (With dataAr[1] being the user entered string I am checking for)

for (var i = 0; i < scList.length; i++) {
   if (dataAr[1] == scList[i]) {
      window.alert(scList[i]+"_sc"[0]);
   }
}

While it is able to match the string to a value in the scList Array properly, the value returned by the window alert is just the user entered string, not showing the "_sc", which makes sense but how could I get this to then relate to the matching variable ending in "_sc"?

To Clarify My hope is that if a user entered "stream" or if dataAr[1] == "stream" that the returned value would be "test0" from stream_sc[0] Thank you for any help!

Zeke Willams · Accepted Answer · 2020-09-16 03:32:52Z

1

You have an extraneous [0] after "_sc" which would grab the underscore and append it to the variable name. What you want is probably scList[i] + "_sc"

You should store them in a json object, so you can reference the sc names to retrieve the values, like so:

const varMap = {
  "stream_sc": [ ],
  "dev_sc": [ ],
  "web_sc": [ ]
};
// access the map using the entered value
varMap[scList[i] + "_sc"][j]
// where j would be the desired item index in the _sc array

I'm currently on a phone, so I hope the formatting comes out ok.

EDIT: fixed some syntax that was needed that the asker pointed out.

edited Sep 16, 2020 at 3:32

answered Sep 12, 2020 at 3:40

Zeke Willams

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1 Comment

confused_techie Over a year ago

This is the solution I ended up using. Thank you, although one edit to the syntax used was needed. Having the final code look something like this. varMap[dataAr[1]+"_sc"][0][0] But that worked perfectly for my project!

dale landry · Accepted Answer · 2020-09-12 03:57:30Z

I assume you dataAR is an array as you make a reference to a key in the conditional dataAr[1]. You could use .includes() in that case to see if your array includes the value of scList[i]... I used a select to show how this could be achieved in a for loop and conditional. If the conditional is true, then rather that using the array scList[i] value use the value that is true... Then concatenate the _sc onto the value and define that as a new variable...

var sel = document.getElementById('sel');
var dataAr = ['gaming']; // array with a value that is not true present already

var scList = ["stream", "dev", "web"];

var stream_sc = ["test0", "test1"];
var dev_sc = ["value", "value"];
var web_sc = ["value", "value"];

function getVal(scList, sel) {
  for (var i = 0; i < scList.length; i++) {
    if (scList.includes(sel.value)) {
      val = sel.value + '_sc';
      return val;
    }
  }
}
let val;
sel.addEventListener("change", function(e) {
  dataAr.push(sel.value);  
  alert(getVal(scList, sel));
  // val myVar = getVal(scList, sel); <-- Do something with this var now
});

<select name="sel" id="sel">

  <option>--select an option below--</option>
  <option value="stream">Twitch</option>
  <option value="dev">Visual Studio Code</option>
  <option value="web">Mozilla</option>
</select>

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