编辑代码

function a(str, w) {
    let index = str.indexOf(w);
    let num = 0;
    while (index !== -1) {
        console.log(index);
        index = str.indexOf(w, index + 1);
        num++;
    }
    return num;
}
let re = a('affeabdcad','a');
console.log(re);