[javascript] Cannot invoke an expression whose type lacks a call signature

I have apple and pears - both have an isDecayed attribute:

interface Apple {
    color: string;
    isDecayed: boolean;
}

interface Pear {
    weight: number;
    isDecayed: boolean;
}

And both types can be in my fruit basket (multiple times):

interface FruitBasket {
   apples: Apple[];
   pears: Pear[];
}

Let's assume for now my basket is empty:

const fruitBasket: FruitBasket = { apples: [], pears: [] };

Now we take randomly one kind out of the basket:

const key: keyof FruitBasket = Math.random() > 0.5 ? 'apples': 'pears'; 
const fruits = fruitBasket[key];

And of course nobody likes decayed fruits so we pick only the fresh ones:

const freshFruits = fruits.filter((fruit) => !fruit.isDecayed);

Unfortunately Typescript tells me:

Cannot invoke an expression whose type lacks a call signature. Type '((callbackfn: (value: Apple, index: number, array: Apple[]) => any, thisArg?: any) => Apple[]) | ...' has no compatible call signatures.

What's wrong here - is it just that Typescript doesn't like fresh fruits or is this a Typescript bug?

You can try it yourself in the official Typescript Repl.

Perhaps create a shared Fruit interface that provides isDecayed. fruits is now of type Fruit[] so the type can be explicit. Like this:

interface Fruit {
    isDecayed: boolean;
}

interface Apple extends Fruit {
    color: string;
}

interface Pear extends Fruit {
    weight: number;
}

interface FruitBasket {
    apples: Apple[];
    pears: Pear[];
}


const fruitBasket: FruitBasket = { apples: [], pears: [] };
const key: keyof FruitBasket = Math.random() > 0.5 ? 'apples': 'pears'; 
const fruits: Fruit[] = fruitBasket[key];

const freshFruits = fruits.filter((fruit) => !fruit.isDecayed);

I had the same issue with numeral, a JS library. The fix was to install the typings again with this command:

npm install --save @types/numeral

As mentioned in the github issue originally linked by @peter in the comments:

const freshFruits = (fruits as (Apple | Pear)[]).filter((fruit: (Apple | Pear)) => !fruit.isDecayed);