SOURCE

function setValue(property="",value,target={}){
    const propertyArr=property.split(".");

    return propertyArr.reduce((pre,cur,index)=>{
        if(index===propertyArr.length-1){
            pre[cur]=value;
            return target;
        }
        pre[cur]={};
        return pre[cur];
    },target)
}

const obj={e:1};

console.log(obj,setValue('a.b.c.d.e',1,obj));