isStarScorable.ts

    // TODO use .flat() or .flatten() instead, but not in this version of JS yet?
    flatten(arrays) {
        return [].concat.apply([], arrays);
    }

    isScorable(posAllStars: number [] [], colors: number []) {
        const starColor = colors[0];

        // Check for every star and collect the results
        return this.flatten(
            posAllStars.map(posStar => this.isStarScorable(posStar, starColor))
        );
    }

    isStarScorable(posStar: number [], color: number) {
        // From the star position, check in every direction if we have a block of the same color
        // If we do, remember it and check the next position in the direction

        const inBounds = ([x, y]) => x !== undefined && y !== undefined && x > 0 && x < this.rows && y > 0 && y < this.cols;
        const gridValue = ([x, y]) => inBounds([x, y]) ? this.grid[x][y] : undefined;

        const goTop = ([x, y]) => [x - 1, y]
        const goBottom = ([x, y]) => [x + 1, y]
        const goLeft = ([x, y]) => [x, y - 1]
        const goRight = ([x, y]) => [x, y + 1]

        const check = (matched: number [], current: number [], color: number, move) => {
            const next = move(current);
            if(gridValue(next) === color)
                return check([...matched, next], next, color, move);
            else
                return matched;
        }

        return this.flatten(
            [
                check([], posStar, color, goTop),
                check([], posStar, color, goBottom),
                check([], posStar, color, goLeft),
                check([], posStar, color, goRight),
            ]
        );
    }

Thanks dude, this helped me a lot, but there is one thing, this only checks in a cross like pattern, i was trying to find all connected gems :P, still, this thought me a lot