js数组对象push前怎么判断是否存在该元素

Question

我用forEach是不是list长度0的时候它不执行,那我for为什么还是不行list=[{id:1,name:'a'},{id:2,name:'b'}]push(action){list.forEach(i=>{if(i.code!==action.code){list.push(action);}})}push(action){for(vari=0;i

Answer 1

push(action){
for(vari=0;iif(list[i].code==action.code){
return;
}
}
list.push(action);
}