The contains() method is defined for a Node: https://developer.mozilla.org/en-US/docs/Web/API/Node.contains TypeScript has it defined on HTMLElement: https://github.com/Microsoft/TypeScript/blob/master/src/lib/dom.generated.d.ts#L272
The contains() method is defined for a Node:
https://developer.mozilla.org/en-US/docs/Web/API/Node.contains
TypeScript has it defined on HTMLElement:
https://github.com/Microsoft/TypeScript/blob/master/src/lib/dom.generated.d.ts#L272