How to Convert String to Variable Name in JavaScript?
Last Updated :
27 Sep, 2024
In JavaScript, if we consider the variable names as string values, it is difficult to transform a variable’s name into a string. However, this problem has been handled in many ways for example, static properties of objects, eval(), and modern ways such as Map can be used to achieve the essential effect of dynamic variable creation, such methods are appropriate for managing dynamic variables.
These are the following approaches to convert a string to a variable name.
Using Object Properties
A JavaScript object is a collection of key-value pairs. Where the key is a string or symbol, you can dynamically assign properties to objects using strings as keys, this method is one of the simplest and most used techniques for simulating the conversion of strings to variable names, this works because objects can access properties and is defined using parentheses that accept strings as keys.
Syntax:
const obj = {};
obj['dynamicKey'] = value;
Example: In this example, We create an empty object obj and dynamically add properties using strings stored in key variables, the username property of the object is created and set to 'Pankaj Kumar Bind', which allows for flexible handling without having to hardcode dynamic attribute names.
JavaScript
const obj = {};
const key = 'username';
obj[key] = 'Pankaj Kumar Bind';
console.log(obj.username);
Using the eval()
Function (Not Recommended)
The eval() function allows you to execute JavaScript code that is expressed as a string although this method can be used to convert strings to variable names by dynamically creating and executing code however it is not strongly recommended, using eval() can lead to severe security vulnerabilities, this is especially true when dealing with user-generated input, it can also negatively impact performance, this forces JavaScript engine to compile new code on the fly.
Syntax:
eval('var ' + variableName + ' = value;');
Example: In the given below example eval() takes a string that forms a JavaScript variable declaration and assigns it a 'dynamic value', although this achieves its goal, using eval() introduces security risks, such as the possibility of running code that dangerous therefore it is generally recommended to avoid this method.
JavaScript
const variableName = 'myVar';
eval('var ' + variableName + ' = "Dynamic Value";');
console.log(myVar);
Using Map
or WeakMap
(Modern Approach)
The map is an interface provided by JavaScript programming language to implement collections of ordered key-value pairs unlike objects where keys are limited to strings or symbols in Map, the keys can be of any data type and this means that Map can perform better than plain old objects at storing dynamic keys and it also provides useful methods like set(), get(), has(), etc thus making it a good approach to deal with such dynamic variable name.
Syntax:
const map = new Map();
map.set(key, value);
Example: In the given below example Map object is used to store dynamic key-value pairs, the string 'age' is set to the key, and the number 25 is stored as its value, unlike simple objects, Map allows more complex key types and has built-in methods for manipulating items, this makes it ideal for dynamic key assignments.
JavaScript
const map = new Map();
const dynamicKey = 'age';
map.set(dynamicKey, 20);
console.log(map.get('age'));
Similar Reads
Non-linear Components In electrical circuits, Non-linear Components are electronic devices that need an external power source to operate actively. Non-Linear Components are those that are changed with respect to the voltage and current. Elements that do not follow ohm's law are called Non-linear Components. Non-linear Co
11 min read
JavaScript Tutorial JavaScript is a programming language used to create dynamic content for websites. It is a lightweight, cross-platform, and single-threaded programming language. It's an interpreted language that executes code line by line, providing more flexibility.JavaScript on Client Side: On the client side, Jav
11 min read
Web Development Web development is the process of creating, building, and maintaining websites and web applications. It involves everything from web design to programming and database management. Web development is generally divided into three core areas: Frontend Development, Backend Development, and Full Stack De
5 min read
Spring Boot Tutorial Spring Boot is a Java framework that makes it easier to create and run Java applications. It simplifies the configuration and setup process, allowing developers to focus more on writing code for their applications. This Spring Boot Tutorial is a comprehensive guide that covers both basic and advance
10 min read
React Interview Questions and Answers React is an efficient, flexible, and open-source JavaScript library that allows developers to create simple, fast, and scalable web applications. Jordan Walke, a software engineer who was working for Facebook, created React. Developers with a JavaScript background can easily develop web applications
15+ min read
Class Diagram | Unified Modeling Language (UML) A UML class diagram is a visual tool that represents the structure of a system by showing its classes, attributes, methods, and the relationships between them. It helps everyone involved in a projectâlike developers and designersâunderstand how the system is organized and how its components interact
12 min read
Steady State Response In this article, we are going to discuss the steady-state response. We will see what is steady state response in Time domain analysis. We will then discuss some of the standard test signals used in finding the response of a response. We also discuss the first-order response for different signals. We
9 min read
JavaScript Interview Questions and Answers JavaScript (JS) is the most popular lightweight, scripting, and interpreted programming language. JavaScript is well-known as a scripting language for web pages, mobile apps, web servers, and many other platforms. Both front-end and back-end developers need to have a strong command of JavaScript, as
15+ min read
React Tutorial React is a JavaScript Library known for front-end development (or user interface). It is popular due to its component-based architecture, Single Page Applications (SPAs), and Virtual DOM for building web applications that are fast, efficient, and scalable.Applications are built using reusable compon
8 min read
Backpropagation in Neural Network Back Propagation is also known as "Backward Propagation of Errors" is a method used to train neural network . Its goal is to reduce the difference between the modelâs predicted output and the actual output by adjusting the weights and biases in the network.It works iteratively to adjust weights and
9 min read