Using parameter in function to call a variable

Question

I have defined a variables outside of a function and I need to be able to call the variable depending on the parameter that is called with the function.

HTML

<button id="Area300" style="left:755px;" onclick="a('normal', 'Area300')"></button>

JAVASCRIPT

var Area300_Data = "somedata"
function a(data, data1) {
  if (data=='extra') {
    //do something
  } else if (data=='normal') {
    console.log(data1+_Data)
    //Should display "somedata"
  }
}

How do I combine the parameter of data1 to _Data to get (in this case) Area300_Data?

use object key value pair

manish
– manish

2019-02-18 10:57:45 +00:00
Commented Feb 18, 2019 at 10:57 — manish
– manish, Commented Feb 18, 2019 at 10:57

brk · Accepted Answer · 2019-02-18 10:58:10Z

3

That may not work unless you use eval. Secondly _Data will act as a variable unless you add it as a string. So either put it inside quotes or use template literals

var Area300_Data = "somedata"

function a(data, data1) {
  if (data == 'extra') {
    //do something
  } else if (data == 'normal') {
    console.log(eval(`${data1}_Data`))
    //Should display "somedata"
  }
}

<button id="Area300" style="left:755px;" onclick="a('normal', 'Area300')" type='button'>Click</button>

answered Feb 18, 2019 at 10:58

brk

50.3k10 gold badges59 silver badges85 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

samb102 Over a year ago

Actually you don't need eval here. var variables are stored into the window object. Except if the code is already into a function context, but it doesn't seem to be the case here.

JackU Over a year ago

I have var Area300_Date defined in a window.onload function (as the data for the variable is from a JSON file). I get the error Area300_Data is not defined at eval How do I correct this?

samb102 · Accepted Answer · 2019-02-18 11:04:48Z

2

If you are in the global scope, every var are stored into window

So you can

window[`${data1}_Data`]

edited Feb 18, 2019 at 11:04

answered Feb 18, 2019 at 10:59

samb102

1,1145 silver badges13 bronze badges

Comments

Rajiv · Accepted Answer · 2019-02-18 10:59:16Z

0

You can keep the data in Object and access that data like property

e.g

var data = {
 Area300_Data : "somedata"
}

Now you can access that data dynamically like this

function a(data, data1) {
  if (data=='extra') {
    //do something
  } else if (data=='normal') {
    console.log(data[data1+'_Data'])
    //Should display "somedata"
  }
}

It will be more readable than accessing window object

answered Feb 18, 2019 at 10:59

Rajiv

1,3051 gold badge15 silver badges30 bronze badges

Comments

Alexus · Accepted Answer · 2019-02-18 11:02:10Z

0

Why don't you try to create an object which uses data1 as a key may be something like that?

var gobalInfo = {
   Area300: "somedata"
}
function a(data, data1) {
  if (data=='extra') {
    //do something
  } else if (data=='normal') {
    console.log(globalInfo[data1]);
    //Should display "somedata"
  }
}

answered Feb 18, 2019 at 11:02

Alexus

1,5121 gold badge14 silver badges23 bronze badges

Comments

Maheer Ali · Accepted Answer · 2019-02-18 11:05:51Z

data1+_Data apply + operator between two variables named data1 and _Data. You can't access the variable like.
In this case Area300_Data is in global scope and declared using var so its present in window. You you access it from window using Bracket Notation []

var Area300_Data = "somedata"
function a(data, data1) {
  if (data=='extra') {
    //do something
  } else if (data=='normal') {
    console.log(window[`${data1}_Data`])
    //Should display "somedata"
  }
}

<button id="Area300" style="left:755px;" onclick="a('normal', 'Area300')">button</button>

However I would prefer to keep the data in and object named Data and access it from there

let Data = {
   Area300:"somedata"
}
var Area300_Data = "somedata"
function a(data, data1) {
  if (data=='extra') {
    //do something
  } else if (data=='normal') {
    console.log(Data[data1])
    //Should display "somedata"
  }
}

<button id="Area300" style="left:755px;" onclick="a('normal', 'Area300')">button</button>

Munna Bhakta · Accepted Answer · 2019-02-18 11:06:37Z

0

simply use eval to get variable data. for example

var Area300_Data = "300 Area Data";
var Area600_Data = "600 Area Data";

function a(data, data1) {
  if (data == 'extra') {
    //do something
  } else if (data == 'normal') {
    console.log(eval(`${data1}_Data`))
    //Should display "somedata"
  }
}

<button onclick="a('normal','Area300')">Click to see Area300</button>
<button onclick="a('normal','Area600')">Click to see Area600</button>

answered Feb 18, 2019 at 11:06

Munna Bhakta

3533 silver badges14 bronze badges

Collectives™ on Stack Overflow

Using parameter in function to call a variable

6 Answers 6

2 Comments

Comments

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

6 Answers 6

2 Comments

Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related