Filter array from multiple to single type

[OliverJAsh]

class Element {
    constructor() {}
}

class Image extends Element {
    constructor(public src: string) { super() }
}

const elements: Element[] = [new Element(), new Image('foo')]

const imageEls: Image[] = elements.filter(e => e instanceof Image)
imageEls

This results in:

main.ts(39,7): error TS2322: Type 'Element[]' is not assignable to type 'Image[]'.
  Type 'Element' is not assignable to type 'Image'.
    Property 'src' is missing in type 'Element'.

Is TypeScript able to infer that the filtered elements array now only contains Images?

[DanielRosenwasser]

Hey @OliverJAsh, check out #7657.