如何在javascript中合并多个对象？

Question

我在javascript中有以下JSON对象数组：

  [{ "AuthorName" : "Abc", "BookName" : "book-1" }]
  [{ "AuthorName" : "Abc", "BookName" : "book-2" }]
  [{ "AuthorName" : "Abc", "BookName" : "book-3" }]
  [{ "AuthorName" : "Abc", "BookName" : "book-4" }]

现在，我想从上面的JSON对象数组创建一个JSON对象。新创建的单个JSON对象包含两个属性：AuthorName和BooKName数组。我正在尝试实现这样的目标：

{ "AuthorName" : "Abc", "Book" : ['book-1', 'book-2', 'book-3', 'book-4'] }

现在我的问题是，我如何才能高效地实现这一点，并且用javascript编写最少的代码呢？

Answer 1

var obj = {};
for(var i=0; i<myArray.length; i++) {
    if(obj[myArray[i].AuthorName] == null)
        obj[myArray[i].AuthorName] = [];
    obj[myArray[i].AuthorName].push(myArray[i].BookName)
}

Answer 2

希望这能有所帮助：

var bookSort = function (bookarray) {
    var i, 
        book,
        authorArray = [],
        il = bookarray.length,
        j,
        jl,
        authorInArray;
    for (i = 0; i < il; i++) {
        authorInArray= false;
        jl = authorArray.length;
        book = bookArray[i];
        for (j = 0; j < jl; j++) {
            if (book.AuthorName = authorArray[j].AuthorName) {
                authorInArray= true;
                authorArray[j].BookName.push(book.BookName);
                break;
            }
        }
        if (!authorInArray) {
            authorArray.push({AuthorName: book.AuthorName, BookName: [book.BookName]});
        }
    }
    return authorArray;
};

Answer 3

看起来你需要一个组合多个对象的函数。

如果你创建了一个通用的函数来做这件事，你可以重用它。我不鼓励你创建一个像authorArray之类的硬编码的解决方案。

让我们创建一个接受多个对象并将它们组合在一起的函数。让我们保持简单，并假设对象看起来与您问题中的对象相似。换句话说，要组合的对象将仅仅是名称值对的平面列表。这些值可以是字符串，也可以是字符串数组。

jsFiddle Demo

// A function that combines multiple object.
//   The original objects are made of name value pairs where the values are strings.
// If - for a key - the values are the same, the value is kept
// If - for a kye - the values are different, and array is created and the values pushed to it
//   after this all new values are added to the array if not already there.
var combineObjects = function() {

                 // see how many object are to be combined
    var length = arguments.length,
        i,
        // Create a new empty object that will be returned
        newObject = {},
        objectIn,
        prop,
        temp,
        ii,
        alreadyExists;

    // Go through all passed in object... combinging them
    for (i = 0; i < length; ++i) {

        objectIn = arguments[i];

        for (prop in objectIn) {
            if (objectIn.hasOwnProperty(prop)) {

                // Check if the prop exisits
                if (newObject[prop]) {

                     // Check if the prop is a single or multiple (array)
                    if (Object.prototype.toString.call( newObject[prop] ) === '[object Array]') {
                        // Multiple

                        // Check if element is in array
                        alreadyExists = false;
                        for (ii = 0; ii < newObject[prop].length; ++ii) {
                            if (newObject[prop][ii] === objectIn[prop]) {
                                alreadyExists = true;
                                break;                                    
                            }
                        }

                        if (! alreadyExists) {
                            newObject[prop].push(objectIn[prop]);
                        }

                    } else {
                        // Single   
                        if (newObject[prop] !== objectIn[prop]) {
                            temp = newObject[prop];
                            newObject[prop] = [temp, objectIn[prop]];                               
                        }
                    }
                } else {
                    newObject[prop] = objectIn[prop];
                }
            }
        }                
    }  

    // Alert for testing
    alert(JSON.stringify(newObject));

    return newObject;        
};