Blaze 模板，遍歷字段？

Question

我一直無法找到任何可用於循環遍歷名為“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結構中的子字段的 object 字段。

我知道每個文檔的 #each 但不知道如何 go 關於每個字段。 我有 30 周的字段，想遍歷這些字段，然后也引用 object 屬性。

任何人都可以給我提示或可能對我有幫助的在線資源嗎？ 我是一名 VB/php 開發人員，正在開發我的第一個 Meteor 應用程序，並且是第一次使用 Mongo。 希望我錯過了一些可能的東西。

    "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 或游標，所以你需要從你的 Object 中提取一個數組。

在 JavaScript 中，您可以從 Object（這是您的文檔）的字段（屬性）生成一個數組，並過濾它們以僅包含屬性名稱（鍵）中包含week的那些。 然后你可以通過助手返回它們：

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
  }
})

然后您可以通過{{#each week in allWeeks}}對其進行迭代。

注意：這有點低效，因為在每次重繪時它都會運行上面的代碼。 您將引入一個 ReactiveVar 或 ReactiveDict 並在其中保存week並從該反應源返回值：

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')
  }
})

讀物：

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