如何合并对象数组？

Question

假设我有一系列文章，每篇文章可能有也可能没有超过 1 个图像对象，现在由于 mysql 不能将对象组合在一起，你必须自己做。所以结果是你得到 near 重复的文章对象......唯一的区别是图像对象。接近重复我的意思是 returned 结果的唯一区别是图像对象。

我试图找到一种方法来遍历 articles 数组并消除重复对象并创建一个 images 数组来保存每个 article 图像对象。

例如给定以下文章数组：

{ articles: [
   {article: {articleId: 10, articleText: 'blah'}, image: {articleId: 10,  imageUrl: 'http://differentUrlTooBelow'} },
   {article: {articleId: 10, articleText: 'blah'}, image: {articleId: 10, imageUrl: 'http://AnotherUrlDifferentToAbove'} },
   {article: {articleId: 11, articleText: 'ajsdnfa'}, image: {articleId: 11, imageUrl: 'http://DifferentUrlTooBelow'} },
   {article: {articleId: 11, articleText: 'asfdjnasjdf'}, image: {articleId: 11, imageUrl: 'http://AnotherUrlDifferentToAbove'} },
]}

我们可以使用 lodash reduce 功能，但它似乎只 return 最后 article (articleId: 11)...它似乎也没有找到所有图像。它只会在每篇文章中创建一个图像数组。请注意 res 是 article 对象的数组（如上所示）

var z = _.reduce(res, function(result, value, key) {
if (key == 0) return;
if(value.article['articleId'] == res[key-1].article['articleId']) {
  result = value;
  result.images = [];
  result.images.push(result.image);
}

return result;
}, {});

最终结果看起来像这样：

{ articles: [
   {article: {articleId: 10, articleText: 'blah'}, 
    images: [
       {articleId: 10,  imageUrl: 'http://differentUrlTooBelow'},
       {articleId: 10, imageUrl: 'http://AnotherUrlDifferentToAbove'} 
   ]},
   {article: {articleId: 11, articleText: 'blah'}, 
    images: [
       {articleId: 11,  imageUrl: 'http://differentUrlTooBelow'},
       {articleId: 11, imageUrl: 'http://AnotherUrlDifferentToAbove'} 
   ]},
]}

Answer 1

可以用_.groupBy()匹配article.articleId，然后_.map()用第一项关联每篇文章，然后设置images属性通过 _.map().

获取所有 image 项

var data = { 
  articles: [
   {
     article: {articleId: 10, articleText: 'blah'}, 
     image: { articleId: 10, imageUrl: 'http://differentUrlTooBelow' } 
   },
   {
     article: {articleId: 10, articleText: 'blah'}, 
     image: { articleId: 10, imageUrl: 'http://AnotherUrlDifferentToAbove' } 
   },
   {
     article: {articleId: 11, articleText: 'ajsdnfa'}, 
     image: { articleId: 11, imageUrl: 'http://DifferentUrlTooBelow' }
   },
   {
     article: {articleId: 11, articleText: 'asfdjnasjdf'}, 
     image: { articleId: 11, imageUrl: 'http://AnotherUrlDifferentToAbove' } 
   }
  ]
};

var result = {
  articles: _(data.articles)
    .groupBy('article.articleId')
    .map(function(items) {
      return _(items[0])
        .omit('image')
        .set('images', _.map(items, 'image'))
        .value();
    })
    .value()
};

document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.11.2/lodash.js"></script>

如何合并对象数组？

How can I merge an array of objects?

javascript

arrays

lodash