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]

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

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; 
});

我的选择是使用.includes()扩展数组。正如@Darrin Dimitrov所建议的原型:

Array.prototype.pushIfNotIncluded = function (element) {
    if (!this.includes(element)) {
      this.push(element);
    }
}

记住include来自es6，在IE上不起作用: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes

http://api.jquery.com/jQuery.unique/

var cleanArray = $.unique(clutteredArray);

你可能对makeArray也感兴趣

前面的例子最好说明在push之前检查它是否存在。 事后看来，它还声明你可以将它声明为原型的一部分(我猜这是又名类扩展)，所以下面没有大的增强。

除了我不确定indexOf是一个更快的路径，然后inArray?可能。

Array.prototype.pushUnique = function (item){
    if(this.indexOf(item) == -1) {
    //if(jQuery.inArray(item, this) == -1) {
        this.push(item);
        return true;
    }
    return false;
}

如果有人有不太复杂的要求，这里是我对一个简单字符串数组的答案的改编:

Array.prototype.pushIfNotExist = function(val) {
    if (typeof(val) == 'undefined' || val == '') { return; }
    val = $.trim(val);
    if ($.inArray(val, this) == -1) {
        this.push(val);
    }
};

更新:替换indexOf和trim与jQuery的IE8兼容性的替代品