让你想更新数组[2]= "data"的值

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

尝试使用forEach(item,index) helper

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"
    }
];

let search_to_change = 'jquery'

projects.forEach((item,index)=>{
   if(item.value == search_to_change )
      projects[index].desc = 'your description ' 
})

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]
        };
    }

要更新多个匹配项，请使用:

_.chain(projects).map(item => {
      item.desc = item.value === "jquery-ui" ? "new desc" : item.desc;
      return item;
    })

这里我使用的是angular js。在javascript中，你可以使用for循环来查找。

    if($scope.bechval>0 &&$scope.bechval!=undefined)
    {

                angular.forEach($scope.model.benhmarkghamlest, function (val, key) {
                $scope.model.benhmarkghamlest[key].bechval = $scope.bechval;

            });
    }
    else {
        alert("Please sepecify Bechmark value");
    }

const state = [
{
    userId: 1,
    id: 100,
    title: "delectus aut autem",
    completed: false
},
{
    userId: 1,
    id: 101,
    title: "quis ut nam facilis et officia qui",
    completed: false
},
{
    userId: 1,
    id: 102,
    title: "fugiat veniam minus",
    completed: false
},
{
    userId: 1,
    id: 103,
    title: "et porro tempora",
    completed: true
}]

const newState = state.map(obj =>
    obj.id === "101" ? { ...obj, completed: true } : obj
);