你必须像这样在数组中搜索:

function changeDesc( value, desc ) {
   for (var i in projects) {
     if (projects[i].value == value) {
        projects[i].desc = desc;
        break; //Stop this loop, we found it!
     }
   }
}

然后像这样使用它

var projects = [ ... ];
changeDesc ( 'jquery-ui', 'new description' );

更新:

为了更快:

var projects = {
   jqueryUi : {
      value:  'lol1',
      desc:   'lol2'
   }
};

projects.jqueryUi.desc = 'new string';

(根据Frédéric的评论，你不应该在对象键中使用连字符，或者你应该使用“jquery-ui”和项目["jquery-ui"]符号。)

ES6方式，不改变原始数据。

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"
}];

//find the index of object from array that you want to update
const objIndex = projects.findIndex(obj => obj.value === 'jquery-ui');

// Make sure to avoid incorrect replacement
// When specific item is not found
if (objIndex === -1) {
  return;
}

// make new object of updated object.   
const updatedObj = { ...projects[objIndex], desc: 'updated desc value'};

// make final new array of objects by combining updated object.
const updatedProjects = [
  ...projects.slice(0, objIndex),
  updatedObj,
  ...projects.slice(objIndex + 1),
];

console.log("original data=", projects);
console.log("updated data=", updatedProjects);

这是另一个涉及到发现的答案。 这取决于以下事实:

遍历数组中的每个对象，直到找到匹配的对象 每个对象都提供给你并且是可修改的

下面是关键的Javascript代码片段:

projects.find( function (p) {
    if (p.value !== 'jquery-ui') return false;
    p.desc = 'your value';
    return true;
} );

下面是相同Javascript的另一个版本:

projects.find( function (p) {
    if (p.value === 'jquery-ui') {
        p.desc = 'your value';
        return true;
    }
    return false;
} );

这里有一个更短的(有点邪恶的版本):

projects.find( p => p.value === 'jquery-ui' && ( p.desc = 'your value', true ) );

以下是完整的工作版本:

let 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" } ]; projects.find( p => p.value === 'jquery-ui' && ( p.desc = 'your value', true ) ); console.log( JSON.stringify( projects, undefined, 2 ) );

这是我对这个问题的回应。我的下划线版本是1.7，因此我不能使用. findindex。

所以我手动获取了item的索引并替换了它。这里是相同的代码。

 var students = [ 
{id:1,fName:"Ajay", lName:"Singh", age:20, sex:"M" },
{id:2,fName:"Raj", lName:"Sharma", age:21, sex:"M" },
{id:3,fName:"Amar", lName:"Verma", age:22, sex:"M" },
{id:4,fName:"Shiv", lName:"Singh", age:22, sex:"M" }
               ]

下面的方法将用对象中更多的属性替换id:4的学生

function updateStudent(id) {
 var indexOfRequiredStudent = -1;
    _.each(students,function(student,index) {                    
      if(student.id === id) {                        
           indexOfRequiredStudent = index; return;      
      }});
 students[indexOfRequiredStudent] = _.extend(students[indexOfRequiredStudent],{class:"First Year",branch:"CSE"});           

}

使用下划线1.8，它将被简化，因为我们有方法_.findIndexOf。

你必须像这样在数组中搜索:

function changeDesc( value, desc ) {
   for (var i in projects) {
     if (projects[i].value == value) {
        projects[i].desc = desc;
        break; //Stop this loop, we found it!
     }
   }
}

然后像这样使用它

var projects = [ ... ];
changeDesc ( 'jquery-ui', 'new description' );

更新:

为了更快:

var projects = {
   jqueryUi : {
      value:  'lol1',
      desc:   'lol2'
   }
};

projects.jqueryUi.desc = 'new string';

(根据Frédéric的评论，你不应该在对象键中使用连字符，或者你应该使用“jquery-ui”和项目["jquery-ui"]符号。)

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
);