falsandtru

class ExIterable<T> implements Iterable<T> {

    protected _source: Iterable<any>; // cheat to drop type param `R`.
    protected _operator: Operator<any, T>; // cheat to drop type param `R`.

    constructor(source: Iterable<T> = null) {
        this._source = source;
        this._operator = null;
    }