Can someone explain why this is happening and how to properly use typescript try catch to handle exceptions?

General Discussions
1

How do I use typescript to try -catch error handling?

I’m encountering an issue in my TypeScript project, where I need to handle errors using try, catch, and finally statements. I know how to use these in JavaScript, but I’m facing a problem with TypeScript.

When I try to define the exception as an argument in the catch statement, it doesn’t accept it. Here’s the code I’m working with:

private handling(argument: string): string {
    try {
        result = this.markLibrary(argument);
    }
    catch(e: Exception) {
        result = e.Message;
    }
    return result;
}

I need to get the exception message, but I’m unable to do so. The error I receive is:

“Catch clause variable cannot have a type annotation.”

Can someone explain why this is happening and how to properly use typescript try catch to handle exceptions?

2

Hi there,

Remove the type annotation from the catch clause:

In TypeScript, the variable in the catch clause cannot have a type annotation. By default, catch variables are of type any. You can simply remove the type annotation from the catch clause, like this:

private handling(argument: string): string {
    let result = '';
    try {
        result = this.markLibrary(argument);
    } catch (e) {
        result = e.message || 'An error occurred';
    }
    return result;
}

Explanation: TypeScript automatically infers the type of the exception as any in the catch block. You can access properties like e.message without needing a specific type annotation.

3

This method returns an array of an object’s own property names. You can then loop through this array to access the properties. Here’s how you can use it:

const obj = { name: "Bob", age: 30, city: "Builderland" };
const keys = Object.keys(obj);
keys.forEach(propt => {
console.log(propt + ": " + obj[propt]);
});

Here, propt will iterate over each key in the keys array, enabling you to access the corresponding values.

4

@tim-khorev I tried using Object.entries() Method: This method returns an array of an object’s key-value pairs, which can be easily iterated using forEach. Here’s an example:

const obj = { name: "Charlie", age: 35, city: "Chocolate City" };
Object.entries(obj).forEach(([propt, value]) => {
console.log(propt + ": " + value);
});

In this case, propt represents each property name, while value represents its corresponding value, providing a straightforward way to access both.

5

This method returns an array of an object’s key-value pairs, which can be easily iterated using forEach.

Here’s an example:

const obj = { name: "Charlie", age: 35, city: "Chocolate City" };
Object.entries(obj).forEach(([propt, value]) => {
console.log(propt + ": " + value);
});

In this case, propt represents each property name, while value represents its corresponding value, providing a straightforward way to access both.