Function to parse domino strings recursive.

domino.ts

/*
Given a string, representing domino tiles chain. Each tile has L-R format, where L and R are numbers from 1..6 range. Tiles are separated by the comma. Some examples of valid S chain are:
1. 1-4,4-2,3-1
2. 6-3
3. 4-3,5-1,2-2,1-3,4-4
Devise a function that, give  a domino string, returns the number of tiles in the longest matching group within S. A matching group is a set of tiles that match and that are subsequent in S. Domino tiles match, if the right side of a tile is the same as the left side of the following tile. 2-4,4-1 are matching tiles, but 5-2,1-6 are not.
domino("1-1,3-5,5-2,2-3,2-4") should return 3.
*/
#!/usr/bin/env node
console.time('timerName');

const domino = (value: string, max: number = 1, count: number = 1) => {
    if (count > max) max = count;

    if (value[4] == undefined) {
        return max;
    } else {
        return domino(value.slice(4), max, (value[2] == value[4]) ? count + 1 : 1);
    }
}

console.log(domino("1-1"));                                     // 1
console.log(domino("1-2,1-2"));                                 // 1
console.log(domino("3-2,2-1,1-4,4-4,5-4,4-2,2-1"));             // 4
console.log(domino("5-5,5-5,4-4,5-5,5-5,5-5,5-5,5-5,5-5,5-5")); // 7
console.log(domino("1-1,3-5,5-5,5-4,4-2,1-3"));                 // 4
console.log(domino("1-2,2-2,3-3,3-4,4-5,1-1,1-2"));             // 3
console.timeEnd('timerName');

export { };