TS1120: An export assignment cannot have modifiers

TypeScript is a powerful superset of JavaScript that introduces static typing, enabling developers to catch errors early in the development process. In TypeScript, we can define types, interfaces, and enums, which help us create more robust and maintainable code. Types are essentially labels we assign to values to indicate what kind of data they are, which improves readability and minimizes bugs. If you're eager to learn more about TypeScript or use AI tools like gpteach to enhance your coding skills, consider subscribing to my blog for regular updates!

What is a Superset Language?

A superset language is one that builds upon the foundation of another language, adding new features while retaining full compatibility with the original. In this case, TypeScript is a superset of JavaScript, meaning any valid JavaScript code is also valid TypeScript code. This allows developers to gradually adopt TypeScript in existing JavaScript projects without rewriting everything.

TS1120: An export assignment cannot have modifiers.

One of the common errors developers encounter when working with TypeScript is the TS1120 error. The error message states: "An export assignment cannot have modifiers." Let’s break down what this means.

An export assignment occurs when you are exporting a single value from a module, typically using the export= syntax. However, this syntax does not allow for the use of modifiers (such as public, private, or protected). This is a key distinction in TypeScript that can lead to confusion.

Code Example Causing TS1120 Error

export = function myFunction() {
    console.log("Hello, world!");
}

In this example, the code is valid; however, if you attempt to add a modifier:

export = public function myFunction() { // This will cause TS1120
    console.log("Hello, world!");
}

This results in the TS1120 error: "An export assignment cannot have modifiers." The solution is simply to remove the public modifier.

Fixing TS1120 Error

To resolve the TS1120 error, ensure that you do not include any access modifiers (public/private/protected) when using the export assignment syntax. Your function should look like this:

export = function myFunction() {
    console.log("Hello, world!");
}

Important to know!

• Export Syntax: TypeScript provides two main ways to export: named exports and default exports. The export assignment export = is used primarily in module patterns.
• No Modifiers: Export assignments cannot have modifiers. Always ensure you're using standard function syntax for such assignments to avoid the TS1120 error.

FAQ's

Q1: What happens if I use an access modifier with an export assignment?
A: TypeScript does not allow access modifiers (e.g., public, private) with export assignments. If you do, you will trigger a TS1120 error.

Q2: What's the difference between named exports and export assignments?
A: Named exports export multiple values and can be imported using {} syntax, while export assignments export a single value and can be imported directly.

Q3: Can I use export default instead?
A: Yes, export default is another valid export syntax that allows you to specify one default export for a module. However, it has different usage patterns compared to export =.

Important to know!

• Single Value Exports: When using export =, you can only export one value. For multiple exports, consider using named exports.
• Module Imports: Consistency in how you import these exports is essential. Understanding the difference between require (for export =) and import (for named/default exports) is vital.

In summary, TS1120: An export assignment cannot have modifiers. It's crucial to remember this rule when you are declaring your exports. Following these guidelines can significantly improve your TypeScript programming experience and help you avoid common pitfalls like the TS1120 error. If you want more insights into TypeScript or programming in general, don't forget to follow my blog for future tutorials!