不确定速度，但stringification + indexOf是一个简单的方法。首先将数组转换为字符串:

let strMyArray = JSON.stringify(myArray);

然后，对于一系列属性-值对，您可以使用:

if (strMyArray.indexOf('"name":"tom"') === -1 && strMyArray.indexOf('"text":"tasty"') === -1) {
   myArray.push({ name: "tom", text: "tasty" });
}

查找整个对象更简单:

if (strMyArray.indexOf(JSON.stringify(objAddMe) === -1) { 
   myArray.push(objAddMe);
}

像这样的吗?

var item = "Hello World";
var array = [];
if (array.indexOf(item) === -1) array.push(item);

与对象

var item = {name: "tom", text: "tasty"}
var array = [{}]
if (!array.find(o => o.name === 'tom' && o.text === 'tasty'))
    array.push(item)

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; 
});

someArray = [{a: 'a1 value', b: {c: "c1 value"},
             {a: 'a2 value', b: {c: "c2 value"}]
newObject = {a: 'a2 value', b: {c: "c2 value"}}

//New object which needs check for duplicity

let isExists = checkForExists(newObject) {
    return someArray.some(function(el) {
        return el.a === newObject.a && el.b.c === newObject.b.c;
    });
}
// write your logic here 
// if isExists is true then already object in an array else you can add

如果你需要一些简单的东西，而不想扩展数组原型:

// Example array
var array = [{id: 1}, {id: 2}, {id: 3}];

function pushIfNew(obj) {
  for (var i = 0; i < array.length; i++) {
    if (array[i].id === obj.id) { // modify whatever property you need
      return;
    }
  }
  array.push(obj);
}

对于字符串数组(但不是对象数组)，你可以通过调用.indexOf()来检查一个项是否存在，如果不存在，则将该项推入数组:

var newItem = "NEW_ITEM_TO_ARRAY"; var array = ["OLD_ITEM_1"， "OLD_ITEM_2"]; array.indexOf(newItem) === -1 ?array.push(newItem): console.log("此项已存在"); console.log(数组)