Returning a variable name in a function (Javascript)

Question

As I'm debugging, I'm consistently writing this bit of code:

a = 2;
// do some operation on variable a
console.log("The a variable is now " + a);

I wondered if I might create a function that shortens that process, like this,

function varlog(x) {
  var vartext = // this is what I don't know
  return "The " + vartext + " variable is now " + x;
}

var a = 2;
console.log(varlog(a));

Two questions,

Is there a better way to solve this problem that I'm not seeing?
If not, what should the vartext be to solve this problem?

Maybe this isn't possible, because what's being passed to the varlog function isn't "a," but "2." Put a different way, varlog doesn't have any idea what "a" is. — Adam Gosnell
– Adam Gosnell, Commented Dec 3, 2021 at 19:07
This isn’t possible. Try something like a = 2; b = 4; console.log({ a, b }); instead. This will log Object { a: 2, b: 4 }. — Sebastian Simon
– Sebastian Simon, Commented Dec 3, 2021 at 19:09
Use a debugger that shows you all variables with their values. Logging something like console.log("a = ", a) should be very short-term and not something to rely upon extensively. — VLAZ
– VLAZ, Commented Dec 3, 2021 at 19:20

Parth Vaghani · Accepted Answer · 2021-12-03 19:53:50Z

3

You can use "Reflect" as below

function easyDebug(variable){

    let name = Reflect.ownKeys(variable)[0];
    let vals = JSON.stringify(variable[name]);
    console.log("The ( "+ name +" ) variable is now = ( " + vals +" )");
}

let a=5;
easyDebug({a});
//Will output
//The ( a ) variable is now = ( 5 )

let arr=[5,6,7];
easyDebug({arr});
//Will output
//The ( arr ) variable is now = ( [5,6,7] )

let obj={"key1":"val1","key2":"val2"};
easyDebug({obj});
//Will output
//The ( obj ) variable is now = ( {"key1":"val1","key2":"val2"} )

let obj2={obj};
easyDebug({obj2});
//Will output
//The ( obj2 ) variable is now = ( {"obj":{"key1":"val1","key2":"val2"}} )

let arrObj = [obj];
easyDebug({arrObj});
//Will output
//The ( arrObj ) variable is now = ( [{"key1":"val1","key2":"val2"}] )

answered Dec 3, 2021 at 19:53

Parth Vaghani

763 bronze badges

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

1 Comment

Sebastian Simon Over a year ago

Well, Reflect really isn’t necessary here; this is also not usually what Reflect is used for (it’s mostly used as the default action in Proxies). This is no different from the other answer.

Nina Scholz · Accepted Answer · 2021-12-03 19:15:50Z

2

By handing over a variable, the name is not known. the only part, where a variable is known, is to use short hand properties, where the variable name is now the property.

function varlog(x) {
    const [k, v] = Object.entries(x)[0];
    return `The ${k} variable is now ${v}`;
}

const a = 2;

console.log(varlog({ a })); // call with short hand property

edited Dec 3, 2021 at 19:15

answered Dec 3, 2021 at 19:09

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

Collectives™ on Stack Overflow

Returning a variable name in a function (Javascript)

2 Answers 2

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related