Variables in JavaScript are named containers that store a value, using the keywords var , const or let . We can assign the value of a string to a named variable.
If we are given a string as input in our program, we can define a variable name with the string by adding the input string as a key into the symbol table. We can add a single character, numeric values, or strings as the associated value to the variable.
A string variable is a variable that holds a character string. It is a section of memory that has been given a name by the programmer. The name looks like those variable names you have seen so far, except that the name of a string variable ends with a dollar sign, $. The $ is part of the name.
Like Seth's answer, but uses Object.keys()
instead:
const varToString = varObj => Object.keys(varObj)[0]
const someVar = 42
const displayName = varToString({ someVar })
console.log(displayName)
You can use the following solution to solve your problem:
const myFirstName = 'John'
Object.keys({myFirstName})[0]
// returns "myFirstName"
Typically, you would use a hash table for a situation where you want to map a name to some value, and be able to retrieve both.
var obj = { myFirstName: 'John' };
obj.foo = 'Another name';
for(key in obj)
console.log(key + ': ' + obj[key]);
In ES6, you could write something like:
let myVar = 'something';
let nameObject = {myVar};
let getVarNameFromObject = (nameObject) => {
for(let varName in nameObject) {
return varName;
}
}
let varName = getVarNameFromObject(nameObject);
Not really the best looking thing, but it gets the job done.
This leverages ES6's object destructuring.
More info here: https://hacks.mozilla.org/2015/05/es6-in-depth-destructuring/
var x = 2;
for(o in window){
if(window[o] === x){
alert(o);
}
}
However, I think you should do like "karim79"
This works for basic expressions
const nameof = exp => exp.toString().match(/[.](\w+)/)[1];
Example
nameof(() => options.displaySize);
Snippet:
var nameof = function (exp) { return exp.toString().match(/[.](\w+)/)[1]; };
var myFirstName = 'Chuck';
var varname = nameof(function () { return window.myFirstName; });
console.log(varname);
Probably pop would be better than indexing with [0], for safety (variable might be null).
const myFirstName = 'John'
const variableName = Object.keys({myFirstName}).pop();
console.log(`Variable ${variableName} with value '${variable}'`);
// returns "Variable myFirstName with value 'John'"
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