TypeScript vs Java object properties

Question

I know TypeScript ain't Java but I thought this could work. Unfortunately I figure out that probably this inside mainFunction is referring to the mainFunction it self, since functions are first-class citizens, right?

class MathClass<T> {
    total: T;
    increment:number = 0;

    constructor(value:T) {
        this.total = value;
    }

    mathFunction(num:T) {
        this.increment++;
        console.log(this.increment + ")" + this.total );
    }
}

var list:Array<number> = [1,2,3,4,5,6];
var mathClass = new MathClass<number>(0);
list.forEach(mathClass.mathFunction);

output:

NaN)undefined
NaN)undefined
NaN)undefined
NaN)undefined
NaN)undefined
NaN)undefined

While in Java 8 I could do this

public class StaticMethodClass<T> implements Consumer<T> {
    private T total;
    private int increment= 0;
    private BiFunction biFunction;

    StaticMethodClass(T value,BiFunction<T,T,T> biFunction) {
        this.total = value;
        this.biFunction = biFunction;
    }

    public void accept(T t) {
        this.increment++;
        this.total = (T) this.biFunction.apply( this.total, t );
        System.out.println(this.increment + ")" + this.total );
    }

    public static void main(String[] args) {
        List<Integer> list = Arrays.asList(1,2,3,4,5,6 );
        list.forEach( new StaticMethodClass<Integer>(6,(a,b) -> a + b) );
    }
}

Output

1)1
2)3
3)6
4)10
5)15
6)21

So is it possible to implement the same in Typescript?

You don’t need to write `-> { return Integer.valueOf(first.intValue()+second.intValue()); }` in Java. Simply `-> first + second` will do. — Holger, Sep 26 '14 at 16:18
Thanks @Holger, do you know why I have to cast the result of the `BiFunction`? — giannis christofakis, Sep 26 '14 at 16:33
You don’t have to cast. `new StaticMethodClass(0, (a, b) -> a + b)` works fine in my setup (Netbeans 8.0, `jdk1.8.0_20`). Btw, you can also simplify `Arrays.asList(new Integer[] { 1,2,3,4,5,6 })` to `Arrays.asList(1,2,3,4,5,6)`. — Holger, Sep 26 '14 at 16:36
@Holger Thanks again, I get this error `Error:(22, 43) java: incompatible types: java.lang.Object cannot be converted to T` I'm using *Intellij IDEA 13.1.4 JRE:1.8.0_20* — giannis christofakis, Sep 26 '14 at 16:49
Short answer is to use `=>` to declare your functions if you want java-like `this` behavior. — recursive, Sep 26 '14 at 16:55

TypeScript vs Java object properties

0 Answers0