Blaze 模板，遍历字段？

问题描述

我找不到任何可用于循环遍历名为“week01”、“week02”、“week03”的字段的快捷方式的引用，我可以在其中引用该字段，该字段是包含子字段的对象相同的结构。

我知道每个文档都有 #each，但不知道如何处理每个字段。我有 30 周的字段，想遍历这些字段，然后也引用对象属性。

谁能给我一个提示或可能对我有帮助的在线资源？我是一名 VB/PHP 开发人员，正在开发我的第一个 Meteor 应用程序，并第一次与 Mongo 合作。希望我错过了一些可能的东西。

    "personId": "rY7XaJJkrdAWaByQK","week01": {
        "date": {
            "$date": "2021-04-07T12:00:00.000Z"
        },"field1": "chunks as necessary","field2": "readable English","field3": "Contrary to popular belief"
    },"week02": {
        "date": {
            "$date": "2021-04-14T12:00:00.000Z"
        },"field1": "consectetur,from","field2": "more recently with desktop","week03": {
        "date": {
            "$date": "2021-04-21T12:00:00.000Z"
        },"field1": "going through","week04": {
        "date": {
            "$date": "2021-04-28T12:00:00.000Z"
        },"field1": "words which don't look","field2": "sure there isn't","week05": {
        "date": {
            "$date": "2021-05-05T12:00:00.000Z"
        },"field1": "only five centuries","field2": "Where can I get some","field3": "infancy. VarIoUs"
    }
} ```

解决方法

#each 仅接受数组或游标，因此您需要从对象中提取一个数组。

在 JavaScript 中，您可以从对象（即您的文档）的字段（属性）生成一个数组，并过滤​​它们以仅包含在其属性名称（键）中包含 week 的那些。然后你可以通过 helper 返回它们：

const document = {
   "personId": "rY7XaJJkrdAWaByQK","week01": {
        "date": {
            "$date": "2021-04-07T12:00:00.000Z"
        },"field1": "chunks as necessary","field2": "readable English","field3": "Contrary to popular belief"
    },"week02": {
        "date": {
            "$date": "2021-04-14T12:00:00.000Z"
        },"field1": "consectetur,from","field2": "more recently with desktop","week03": {
        "date": {
            "$date": "2021-04-21T12:00:00.000Z"
        },"field1": "going through","week04": {
        "date": {
            "$date": "2021-04-28T12:00:00.000Z"
        },"field1": "words which don't look","field2": "sure there isn't","week05": {
        "date": {
            "$date": "2021-05-05T12:00:00.000Z"
        },"field1": "only five centuries","field2": "Where can I get some","field3": "infancy. Various"
    }
}

const weeks = Object.entries(document) // will be an array of key/value pairs
  .filter(([key,value]) => key.includes('week')) // only use week fields
  .map(([key,value]) => value) // only use the value

Template.helpers({
  allWeeks () {
    return weeks
  }
})

然后您可以通过 {{#each week in allWeeks}} 对其进行迭代。

注意：这有点低效，因为在每次重绘时它都会运行上面的代码。您将引入一个 ReactiveVar 或 ReactiveDict 并将 week 保存在那里并从这个反应源返回值：

const state = new ReactiveDict()
const weeks = Object.entries(document) // will be an array of key/value pairs
  .filter(([key,value]) => value) // only use the value

state.set({ weeks })


Template.helpers({
  allWeeks () {
    return state.get('weeks')
  }
})

阅读：

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

https://docs.meteor.com/api/reactive-dict.html