Getting an Error on Ion Cord

Question

Just started to study the ion signal. 3. Error below ionic cordova build android

 (node:6364) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): [object Object] (node:6364) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code. 

Below is my ion information.

 cli packages: (C:\Users\HIT\AppData\Roaming\npm\node_modules) @ionic/cli-utils : 1.19.0 ionic (Ionic CLI) : 3.19.0 global packages: cordova (Cordova CLI) : 8.0.0 local packages: @ionic/app-scripts : 3.1.6 Cordova Platforms : none Ionic Framework : ionic-angular 3.9.2 System: Node : v8.5.0 npm : 5.3.0 OS : Windows 10 Environment Variables: ANDROID_HOME : D:\AndroidSdk\platform-tools Misc: backend : pro 

I wrote below the promise code

  postData(credentials, type) { return new Promise((resolve, reject) => { let headers = new Headers(); this.http.post(apiUrl+type, JSON.stringify(credentials), {headers: headers}) .subscribe(res => { resolve(res.json()); }, (err) => { reject(err); }); }); } 

I call the postData function below

 signup(){ //Api connection this.authService.postData(this.userData , "register.php").then((result) => { this.reposeData = result; console.log(this.reposeData); localStorage.setItem('userData' , JSON.stringify(this.reposeData)) this.navCtrl.push(TabsPage); }, (err) => { //connection failed }); 

}

Is this the problem of my code?

Answer 1

According to the error message, you did not handle the failure on one of the Promise objects. Each promise is expected to have .catch (...).

 var flag = false; var Test = function () { return new Promise(function (resolve, reject) { if (flag === true) resolve(); else reject(); }); } var testFunc = Test(); testFunc.then(function () { alert("Promise Resolved"); }); testFunc.catch(function () { alert("Promise Rejected"); }); 

Learn more about Promise Objects here.