gistfile1.js

function plus(a, b){
    switch (a) {
        case "0":
            switch (b) {
                case "0": return 0;
                case "1": return 1;
                case "2": return 2;
                case "3": return 3;
                case "4": return 4;
                case "5": return 5;
                case "6": return 6;
                case "7": return 7;
                case "8": return 8;
                case "9": return 9;
            }
            break;

        case "1":
            switch (b) {
                case "0": return 1;
                case "1": return 2;
                case "2": return 3;
                case "3": return 4;
                case "4": return 5;
                case "5": return 6;
                case "6": return 7;
                case "7": return 8;
                case "8": return 9;
                case "9": return 10;
            }
            break;

        case "2":
            switch (b) {
                case "0": return 2;
                case "1": return 3;
                case "2": return 4;
                case "3": return 5;
                case "4": return 6;
                case "5": return 7;
                case "6": return 8;
                case "7": return 9;
                case "8": return 10;
                case "9": return 11;
            }
            break;
    }

    throw new Error("unsupported arguments"):
}