Try - catch() not catching errors and throwing it instead

Question

I have a method in a class that is supposed to only throw error log messages and then another method in another function that will get this errors and console them (for now).

The problem is that it just throws the error in the console and not in an upper level...

This are the methods from file1.ts:

private sendToApp2(App2Url: string, logObject: object) {
    try
    {
        let uriOptions = {
            host: this.hostname,
            port: this.port,
            path: '/App2',
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'Api-version': '1'
            }
        };

       this.App2Call(uriOptions, JSON.stringify(logObject));
    }
    catch (err) {
        throw err;
    }
}

private App2Call(params: Object, data: string) {
    return new Promise((resolve, reject) => {
        try {
            let req = http.request(params, (response) => {
                response.on('data', (data) => {
                    resolve(data);
                });

            }).on('error', (err: Error) => {
                reject(new Error(err.message));
            });

            req.write(data);
            req.end();
        }
        catch (err) {
            reject(new Error(err.message));
        }
    });
}

And in the second file, I do this logic to catch the error and console it:

GetErrors() {
        try {
            // initialize the class object    

            let getErrors = new FirstClass();
            await getErrors.sendToApp2(this.App2Url, this.logObject);
        }
        catch (err) {
            console.log(err);
        }
    }

user_157247 · Answer

It looks like a simple case of having forgotten to use async on the definition of sendToApp2. Since it's not async, there are no errors thrown during sendToApp2 since it returns before the promise from App2Call rejects.

Where you're using sendToApp2 you're using await, which suggests you're expecting it to return a promise, so just add async to the definition:

private async sendToApp2(App2Url: string, logObject: object) {
//      ^^^^^

Then the try/catch can handle rejections as errors.

Side note: Right now, there's no point to the try/catch in sendToApp2, since all it does is throw err.

user_1906356 · Answer

return a promise from the sendToApp2 and deal with the errors when you call the function

private sendToApp2(App2Url: string, logObject: object) {
        let uriOptions = {
            host: this.hostname,
            port: this.port,
            path: '/App2',
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'Api-version': '1'
            }
        };

       return this.App2Call(uriOptions, JSON.stringify(logObject));
}
etErrors.sendToApp2(this.App2Url, this.logObject).then(
     function(){},
     function(err){ //error callback,or you can use catch();
       alert(err);
});

Try - catch() not catching errors and throwing it instead

2 Answers