Calling function in typescript not working in alertify.js

Question

I'm using alertify plugin in typescript and it can't recognize the getData function. Please see below code

copyTemplate(id:any, pluginId:any, name:any ) {
     alertify.confirm(`Are you sure you want to copy ${name} to a new project template?`, function () {
        this.getData();
     }, function() {
          (<HTMLInputElement>document.getElementById('prefGroup')).value = '0';
     });
}

What's wrong with it? Error in browser:

core.umd.js:3064 EXCEPTION: this.getData is not a functionErrorHandler.handleError @ core.umd.js:3064next @ core.umd.js:8039schedulerFn @ core.umd.js:3689SafeSubscriber.__tryOrUnsub @ Subscriber.ts:238SafeSubscriber.next @ Subscriber.ts:190Subscriber._next @ Subscriber.ts:135Subscriber.next @ Subscriber.ts:95Subject.next @ Subject.ts:61EventEmitter.emit @ core.umd.js:3675NgZone.triggerError @ core.umd.js:4038onHandleError @ core.umd.js:3999ZoneDelegate.handleError @ zone.js?1489977130473:207Zone.runTask @ zone.js?1489977130473:139ZoneTask.invoke @ zone.js?1489977130473:304 core.umd.js:3069 ORIGINAL STACKTRACE:ErrorHandler.handleError @ core.umd.js:3069next @ core.umd.js:8039schedulerFn @ core.umd.js:3689SafeSubscriber.__tryOrUnsub @ Subscriber.ts:238SafeSubscriber.next @ Subscriber.ts:190Subscriber._next @ Subscriber.ts:135Subscriber.next @ Subscriber.ts:95Subject.next @ Subject.ts:61EventEmitter.emit @ core.umd.js:3675NgZone.triggerError @ core.umd.js:4038onHandleError @ core.umd.js:3999ZoneDelegate.handleError @ zone.js?1489977130473:207Zone.runTask @ zone.js?1489977130473:139ZoneTask.invoke @ zone.js?1489977130473:304 core.umd.js:3070 TypeError: this.getData is not a function at Object.eval [as onOkay] (project-templates.component.ts:126) at HTMLButtonElement. (alertify.js?1489977130519:280) at ZoneDelegate.invokeTask (zone.js?1489977130473:236) at Object.onInvokeTask (core.umd.js:3969) at ZoneDelegate.invokeTask (zone.js?1489977130473:235) at Zone.runTask (zone.js?1489977130473:136) at HTMLButtonElement.ZoneTask.invoke (zone.js?1489977130473:304)ErrorHandler.handleError @ core.umd.js:3070next @ core.umd.js:8039schedulerFn @ core.umd.js:3689SafeSubscriber.__tryOrUnsub @ Subscriber.ts:238SafeSubscriber.next @ Subscriber.ts:190Subscriber._next @ Subscriber.ts:135Subscriber.next @ Subscriber.ts:95Subject.next @ Subject.ts:61EventEmitter.emit @ core.umd.js:3675NgZone.triggerError @ core.umd.js:4038onHandleError @ core.umd.js:3999ZoneDelegate.handleError @ zone.js?1489977130473:207Zone.runTask @ zone.js?1489977130473:139ZoneTask.invoke @ zone.js?1489977130473:304 Subscriber.ts:241 Uncaught TypeError: this.getData is not a function

Answer 1

use an arrow function. The scope of "this" is different inside the callback

copyTemplate(id:any, pluginId:any, name:any ) {
 alertify.confirm('Are you sure you want to copy ${name} to a new project template?',  () => {
    this.getData();
 }, () => {
      (<HTMLInputElement>document.getElementById('prefGroup')).value = '0';
 });

}

or store the value of this outside the function and use it

copyTemplate(id:any, pluginId:any, name:any ) {
 let self = this;
 alertify.confirm('Are you sure you want to copy ${name} to a new project template?',  function() {
    self.getData();
 }, function() {
      (<HTMLInputElement>document.getElementById('prefGroup')).value = '0';
 });

}