Get object property name as a string

I know a best practice that using Object.keys(your_object). It will parse to array property name for you. Example:

var person = { firstName: 'John', lastName: 'Cena', age: '30' };
var listPropertyNames = Object.keys(person); //["firstName", "lastName", "age"]

I hope this example is useful for you.

You can accomplish this by converting all object properties into functions which will return the their own names

var person = {};
person.firstname = 'Jack';
person.address = "123 Street";

function getPropertyName(obj, expression) {
    var res = {};
    Object.keys(obj).map(k => { res[k] = () => k; });
    return expression(res)();
}

let result = getPropertyName(person, o => o.address);
console.log(result); // Output: 'address'

You can wrap your property in a function and then convert the function to a string and get the property out of it.

For example:

function getPropertyName(propertyFunction) {
    return /\.([^\.;]+);?\s*\}$/.exec(propertyFunction.toString())[1];
}

Then to use it:

var myObj = {
    myProperty: "testing"
};

getPropertyName(function() { myObj.myProperty; }); // myProperty

Beware that minifiers could break this.

Edit: I have created a compiler transform that works with babel and the typescript compiler (see ts-nameof). This is a much more reliable than doing something at runtime.

If anyone's looking for a TypeScript version of MarsRobot's answer, try this:

function nameof<T>(obj: T, expression: (x: { [Property in keyof T]: () => string }) => () => string): string
{
    const res: { [Property in keyof T]: () => string } = {} as { [Property in keyof T]: () => string };

    Object.keys(obj).map(k => res[k] = () => k);

    return expression(res)();
}

Usage:

const obj = { 
    property1: 'Jim',
    property2: 'Bloggs',
    property3: 'Bloggs',
    method: () => 'a string',
    child: { property4: 'child1' }
};

const test1 = nameof(obj, x => x.property1);
const test2 = nameof(obj, x => x.property2);
const test3 = nameof(obj, x => x.method);
const test4 = nameof(obj.child, x => x.property4);

console.log(test1);    // -> 'property1'
console.log(test2);    // -> 'property2'
console.log(test3);    // -> 'method'
console.log(test4);    // -> 'property4'

This version works even when objects have multiple properties with the same value (unlike some of the other answers above), and with editors like Visual Studio will provide intellisense for the property names when you get here: nameof(obj, x => x.

Get object property name as a string

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