用hasOwnProperty去除重复

Question

假设我们有一个目标：

message { 
  diff: { 
    cat: "Tabby"
    name: "Meow Meow"
  }
}

您能用hasOwnProperty()检查副本并删除副本吗？示例

for (key in message.diff) {
   //outputs every change when all keys are updated
   if (message.diff.hasOwnProperty(key)){
     this.uniqueArray.push(key); 
   }
}

编辑:我意识到我想要谈论的内容可能有些混乱。我有一个函数，它侦听任何可以更新的表单元素，它将输入记录到控制台中。它主要是侦听属性名称，这个属性名称输出到数组，数组可能包含或不包含名称的重复项。

如果我们多次更新表单字段，它将变成：

Current Output: ['name', 'name', 'name', 'cat']
Desired Ouput: ['name', 'cat']

Answer 1

您可以使用Object.keys()、Array.prototype.filter()、Array.prototype.includes()来检查对象的属性是否是数组、Array.prototype.push()、扩展元素的一个元素。

​

var message = { 
  diff: { 
    cat: "Tabby",
    name: "Meow Meow"
  }
}

var arr = ["name", "cat"];

arr.push(...Object.keys(message.diff).filter(function(diff) {return !arr.includes(diff)}));

console.log(arr);

var message = { 
  diff: { 
    lion: "Tabby",
    tiger: "Meow Meow"
  }
}

arr.push(
  ...Object.keys(message.diff)
  .filter(function(diff) {return !arr.includes(diff)}))

console.log(arr);

​

Answer 2

检查数组中不存在对象键

for (key in message.diff) {
   //outputs every change when all keys are updated
   if (message.diff.hasOwnProperty(key) &&  this.uniqueArray.indexOf(key) == -1){
     this.uniqueArray.push(key); 
   }
}