How to do error handling in post http in angular 4?

Question

I'm trying to make this post call when user closes the window.

createCallRecord (data) {
        let logData = {"chathist" : data , "uid": "1111" };
        let headers = new HttpHeaders();
        headers = headers.set("Content-Type", "application/json");
        let options = { headers: headers };
        return this.http.post(MY_URL, logData, options).subscribe(res => alert(res));
}

Since this is called when the user closes the window, i don't know whether it's posting sucessfully or not.

How to handle success or error after posting?

For now, it is not alerting anything.

Any help would be appreciated!

Answer 1

You can handle the error in this way:

createCallRecord (data) {
    let logData = {"chathist" : data , "uid": "1111" };
    let headers = new HttpHeaders();
    headers = headers.set("Content-Type", "application/json");
    let options = { headers: headers };
    return this.http.post(MY_URL, logData, options)
        .subscribe(result =>
        {
          let value = result.json();
          console.log(JSON.stringify(value));
        }, err => { console.log(err); });

Another option is to use handler funtion in this way:

createCallRecord (data) {
    let logData = {"chathist" : data , "uid": "1111" };
    let headers = new HttpHeaders();
    headers = headers.set("Content-Type", "application/json");
    let options = { headers: headers };
    return this.http.post(MY_URL, logData, options)
        .subscribe(res => this.resultHadler(res), err => this.errorHandler(err));
}

private resultHadler(res: any)
{
    let value = res.json();
    console.log(JSON.stringify(value));
}

private errorHandler(err: any)
{
    console.log(err);
}