Blaze 模板，遍历字段？

Question

我一直无法找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，我可以在其中引用包含相同结构中的子字段的 object 字段。

我知道每个文档的 #each 但不知道如何 go 关于每个字段。 我有 30 周的字段，想遍历这些字段，然后也引用 object 属性。

任何人都可以给我提示或可能对我有帮助的在线资源吗？ 我是一名 VB/php 开发人员，正在开发我的第一个 Meteor 应用程序，并且是第一次使用 Mongo。 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",
        "field3": "Contrary to popular belief"
    },
    "week03": {
        "date": {
            "$date": "2021-04-21T12:00:00.000Z"
        },
        "field1": "going through",
        "field2": "readable English",
        "field3": "Contrary to popular belief"
    },
    "week04": {
        "date": {
            "$date": "2021-04-28T12:00:00.000Z"
        },
        "field1": "words which don't look",
        "field2": "sure there isn't",
        "field3": "Contrary to popular belief"
    },
    "week05": {
        "date": {
            "$date": "2021-05-05T12:00:00.000Z"
        },
        "field1": "only five centuries",
        "field2": "Where can I get some",
        "field3": "infancy. Various"
    }
} ```

Answer 1

#each只接受 arrays 或游标，所以你需要从你的 Object 中提取一个数组。

在 JavaScript 中，您可以从 Object（这是您的文档）的字段（属性）生成一个数组，并过滤它们以仅包含属性名称（键）中包含week的那些。 然后你可以通过助手返回它们：

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",
        "field3": "Contrary to popular belief"
    },
    "week03": {
        "date": {
            "$date": "2021-04-21T12:00:00.000Z"
        },
        "field1": "going through",
        "field2": "readable English",
        "field3": "Contrary to popular belief"
    },
    "week04": {
        "date": {
            "$date": "2021-04-28T12:00:00.000Z"
        },
        "field1": "words which don't look",
        "field2": "sure there isn't",
        "field3": "Contrary to popular belief"
    },
    "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 并在其中保存week并从该反应源返回值：

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

state.set({ weeks })


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

读物：

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