当心JavaScript奇葩的逗号表达式

  let a = 2;
    switch (a) {
        case (3, 2, 5):
            console.log(1);
            break
        case (2, 3, 4):
            console.log(2);
            break
        case (3, 2):
            console.log(3);
            break
        default:
            console.log(4);
            break;
    }

        let i, j;
        let result = 0;
        for (i = 0, j = 0; i < 3, j < 7; i++, j++) {
            result = i + j
        }
        console.log(result)