我建议你使用Set，

集只允许唯一的条目，这将自动解决您的问题。

集合可以这样声明:

const baz = new Set(["Foo","Bar"])

你可以用一个自定义方法扩展Array原型:

// check if an element exists in array using a comparer function
// comparer : function(currentElement)
Array.prototype.inArray = function(comparer) { 
    for(var i=0; i < this.length; i++) { 
        if(comparer(this[i])) return true; 
    }
    return false; 
}; 

// adds an element to the array if it does not already exist using a comparer 
// function
Array.prototype.pushIfNotExist = function(element, comparer) { 
    if (!this.inArray(comparer)) {
        this.push(element);
    }
}; 

var array = [{ name: "tom", text: "tasty" }];
var element = { name: "tom", text: "tasty" };
array.pushIfNotExist(element, function(e) { 
    return e.name === element.name && e.text === element.text; 
});

这里你有一种方法可以在一行中为两个数组做这件事:

const startArray = [1,2,3,4]
const newArray = [4,5,6]

const result = [...startArray, ...newArray.filter(a => !startArray.includes(a))]

console.log(result);
//Result: [1,2,3,4,5,6]

我有这个问题，我做了一个简单的原型，使用它，如果你喜欢它

Array.prototype.findOrPush = function(predicate, fallbackVal) {
    let item = this.find(predicate)
    if(!item){
        item = fallbackVal
        this.push(item)
    }
    return item
}

let arr = [{id: 1}]
let item = arr.findOrPush(e => e.id == 2, {id: 2})
console.log(item) // {id: 2} 

// will not push and just return existing value
arr.findOrPush(e => e.id == 2, {id: 2}) 
conslog.log(arr)  // [{id: 1}, {id: 2}]

当你希望通过对象的特定属性进行搜索时，我使用了map和reduce来做到这一点，因为直接进行对象相等通常会失败。

var newItem = {'unique_id': 123};
var searchList = [{'unique_id' : 123}, {'unique_id' : 456}];

hasDuplicate = searchList
   .map(function(e){return e.unique_id== newItem.unique_id})
   .reduce(function(pre, cur) {return pre || cur});

if (hasDuplicate) {
   searchList.push(newItem);
} else {
   console.log("Duplicate Item");
}

推动动态

var a = [
  {name:"bull", text: "sour"},
  {name: "tom", text: "tasty" },
  {name: "Jerry", text: "tasty" }
]

function addItem(item) {
  var index = a.findIndex(x => x.name == item.name)
  if (index === -1) {
    a.push(item);
  }else {
    console.log("object already exists")
  }
}

var item = {name:"bull", text: "sour"};
addItem(item);

用简单的方法

var item = {name:"bull", text: "sour"};
a.findIndex(x => x.name == item.name) == -1 ? a.push(item) : console.log("object already exists")

如果数组只包含基元类型/简单数组

var b = [1, 7, 8, 4, 3];
var newItem = 6;
b.indexOf(newItem) === -1 && b.push(newItem);