JSON合并以及合并子项

合并a,b的json,并且以b覆盖a的同类项

function joinJson(a,b) {
    var c = {};
    for(var key in a){
        if(b[key]){
            if(Object.prototype.toString.call(b[key]) === "[object Array]" || Object.prototype.toString.call(b[key])==='[object Object]'){
                c[key] = joinJson(a[key],b[key]);        
            }else {
                c[key] = b[key];
                console.log(c[key])
            }
        }
    }
    return {
        ...a,
        ...b,
        ...c,
    };
}