How Can I Get a JavaScript Variable Name as a String?

Retrieving Variable Names as Strings in JavaScript

In JavaScript, obtaining a variable name as a string is not a straightforward task. Unlike Objective-C's NSStringFromSelector, JavaScript doesn't provide a built-in function for this purpose. However, there is a clever solution to this problem.

Solution

To get a variable name as a string, use the following trick:

const myFirstName = 'John'
Object.keys({myFirstName})[0]

This expression produces a temporary object literal with the variable name as the key and its value. Then, the Object.keys() method is used to extract the key and return it as a string.

Understanding the Solution

The code creates an object literal with the variable name as a property. Since object keys are always strings, it effectively converts the variable name to a string. The Object.keys() method then retrieves all the keys from the object, which in this case is just the variable name. By accessing the first element of the keys array, we obtain the string representation of the variable name.

Example

var myFirstName = 'John';
alert(Object.keys({myFirstName})[0] + ":" + myFirstName);

--> myFirstName:John

Applications

This technique can be useful in various scenarios, such as debugging, code introspection, and communication between different contexts like your example of sending instance names from a browser to another program. By using the variable's name as a string, you can dynamically invoke methods or perform other operations based on variable names.

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