upsert(array, item) { 
        const i = array.findIndex(_item => _item.id === item.id);
        if (i > -1) {
            let result = array.filter(obj => obj.id !== item.id);
            return [...result, item]
        }
        else {
            return [...array, item]
        };
    }

// using higher-order functions to avoiding mutation var projects = [ { value: "jquery", label: "jQuery", desc: "the write less, do more, JavaScript library", icon: "jquery_32x32.png" }, { value: "jquery-ui", label: "jQuery UI", desc: "the official user interface library for jQuery", icon: "jqueryui_32x32.png" }, { value: "sizzlejs", label: "Sizzle JS", desc: "a pure-JavaScript CSS selector engine", icon: "sizzlejs_32x32.png" } ]; // using higher-order functions to avoiding mutation index = projects.findIndex(x => x.value === 'jquery-ui'); [... projects.slice(0,index), {'x': 'xxxx'}, ...projects.slice(index + 1, projects.length)];

让你想更新数组[2]= "data"的值

    for(i=0;i<array.length;i++){
      if(i == 2){
         array[i] = "data";
        }
    }

它可以很容易地用下划线/lodash库完成:

  _.chain(projects)
   .find({value:"jquery-ui"})
   .merge({desc: "new desc"}).value();

文档: https://lodash.com/docs#find https://lodash.com/docs#merge

我们可以这样改变

const oldArray = [{username: gopal, age: 20}, {username: gopi, age: 21}]
const obj = {username: gopal, age: 25}
const result = oldArray.map(d => d.username === 'gopi' ? d.age = obj.age : d)

您可以像下面这样创建特定的函数，然后在需要的任何地方使用它。

var each    = (arr, func) => 
                Array.from(
                    (function* (){
                        var i = 0;
                        for(var item of arr)
                            yield func(item, i++);
                    })()
                );

享受. .