Saving The Application State On Cordovas Pause With Angular

I've got a Cordova app running on my Android device to show some news retrieved from a web service. As I'm using Typescript and Angular I've got a service holding my news like so:

Solution 1:

When you define your event binding in

document.addEventListener('pause', this.saveNews, false);

your method is simply not declared yet. Take a look at this TypeScript example:

classTest {
    greeting: string;
    constructor(message: string) {
        console.log(greet)
    }
    greet() {
        return"Hello, " + this.greeting;
    }
}

It transpiles to this JavaScript:

varTest = (function () {
    functionTest(message) {
        console.log(greet);
    }
    Test.prototype.greet = function () {
        return"Hello, " + this.greeting;
    };
    returnTest;
})();

You would expect to get a function-reference, but hoisting wont work here, because every method is a reference for an anonymous function and the prototype-fields for these functions are simply not declared yet.

Encapsulate it in a lambda function will work:

document.addEventListener('pause', ()=>this.saveNews(), false);