时间戳

首页 > 解决方案 > javascript将数组对象拆分为给定大小的对象数组

javascript - javascript将数组对象拆分为给定大小的对象数组

问题描述

我有一个具有一些属性的对象，例如：

const rows_obj = {
    prova1:[{price:3,description:"test11"},{price:7,description:"test12"}],
    prova2:[{price:11,description:"test21"},{price:2,description:"test22"}],
    prova3:[{price:1,description:"test31"},{price:23,description:"test32"}],
}

我需要在一页或多页中打印行，所以每页的限制是例如 3 行。所以在这种情况下，我需要一个对象 obj 数组，例如：

obj[0] = {
        total:21,
        prova1:[{price:3,description:"test11"},{price:7,description:"test12"},],
        prova2:[{price:11,description:"test21"}],
    }

obj[1] = {
        total:26,
        prova2:[{price:2,description:"test22"}],
        prova3:[{price:1,description:"test31"},{price:23,description:"test32"},],
    }

（因为在这种情况下，限制是每页/对象 3 行）

但限制也可能是 20 行，因此最终对象将是：

obj[0] = {
        total:47,
        prova1:[{price:3,description:"test11"},{price:7,description:"test12"},],
        prova2:[{price:11,description:"test21"},{price:2,description:"test22"},],
        prova3:[{price:1,description:"test31"},{price:23,description:"test32"},],
    }

因为在原始对象中有 6 行，那么，由于在限制之下，函数必须检索一个包含一个元素的数组，并且这个元素等于原始元素。

我试过了，但到目前为止我已经做了这个代码：

const size = 3
const rows_obj = {
    prova1:[{price:22,description:"test11"},{price:23,description:"test12"},],
    prova2:[{price:22,description:"test21"},{price:23,description:"test22"},],
    prova3:[{price:22,description:"test31"},{price:23,description:"test32"},],
}

var rows_length = 0;

for(var char in rows_obj){
  // Confirm that the key value is an array before adding the value.
  if(Array.isArray(rows_obj[char])){
    rows_length += rows_obj[char].length;   
  }
}

  if (!rows_length) {
    return [[]]
  }

  const arrays = []
  let i = 0

  const keys = Object.keys(rows_obj)
  let obj = null
  
  while (i<rows_length) {
    obj = {}
    for(let j=0;j<keys.length;j++) {
      obj[keys[j]] = rows_obj[keys[j]].slice(i, i + size)
      i = i + 2 + size
      console.log(i)
    } 
    arrays.push(obj)
  }

它不工作，我做的一团糟......有什么帮助吗？先感谢您。

标签： javascriptalgorithm

解决方案

使用Object#entries,Array#reduce和Array#forEach:

const 
  rows_obj = {
    prova1:[{price:3,description:"test11"},{price:7,description:"test12"}],
    prova2:[{price:11,description:"test21"},{price:2,description:"test22"}],
    prova3:[{price:1,description:"test31"},{price:23,description:"test32"}],
  },
  SIZE = 3;
let count = 0; // count of items in last object

const rowEntries = Object.entries(rows_obj);
// iterate over rows_obj entries while updating finalList
const res = rowEntries.reduce((finalList, [currentKey, currentItems]) => {
  // iterate over current items
  currentItems.forEach(item => {
    // if SIZE is reached in the last object, add new one
    if(count === SIZE) {
      count = 0;
      finalList.push({ total: 0 });
    }
    // update last object
    const last = finalList[finalList.length-1];
    finalList[finalList.length-1] = {
      ...last,
      total:        last.total + item.price,
      [currentKey]: [...(last[currentKey] || []), item]
    };
    count++;
  });
  return finalList;
}, rowEntries.length > 0 ? [{ total: 0 }] : []);

console.log(res);

推荐阅读