I was just wondering if it is possible to type array with a union type, so that one array can contain both Apples and Oranges but nothing else.
Something like
var arr : (Apple|Orange)[] = [];
arr.push(apple); //ok
arr.push(orange); //ok
arr.push(1); //error
arr.push("abc"); // error
Needless to say, the example above does not work so this may not be possible, or am I missing something?
class Apple {
appleFoo: any;
}
class Orange {
orangeFoo: any;
}
var arr : Array<Apple|Orange> = [];
var apple = new Apple();
var orange = new Orange();
arr.push(apple); //ok
arr.push(orange); //ok
arr.push(1); //error
arr.push("abc"); // error
var something = arr[0];
if(something instanceof Apple) {
something.appleFoo; //ok
something.orangeFoo; //error
} else if(something instanceof Orange) {
something.appleFoo; //error
something.orangeFoo; //ok
}
if (arr[0].hasOwnProperty("name")) { var a = <Apple>arr[0]; console.log(a.name); }
As per TS 2.3.4 is as simple as
let someArray: (typeA|typeB)[] = [
new typeA(),
new typeB()
]
