[英]How to sort an array of components in React Native?
我有一個嵌套映射來遍歷我的數據,然后為我的數據中的每個對象返回一個反應組件。 檢查下面的代碼:
return props.dataArray.map((classObj) => {
return classObj.timetable.map((timetableObj) => {
if (timetableObj.weekday === props.day) {
return ttCard({
lecturer: classObj.lecturer,
module: classObj.module,
room: classObj.room,
class_id: classObj.id,
timetable_id: timetableObj.id,
startTime: timetableObj.start_time,
endTime: timetableObj.end_time,
weekday: timetableObj.weekday
});
}
return null;
});
});
我的問題是我的組件沒有排序,它們必須排序,因為它是學生的時間表。 查看下圖並注意 10:30 AM 是我的選項卡視圖中最新的卡片:
到目前為止我嘗試過的事情:
1- 創建一個新數組,然后在if statement
塊之后對其進行排序 - 不起作用 2- 將排序后的數組返回到函數並映射該數組以返回組件 - 不起作用 3- 循環並將對象作為組件內的函數返回范圍:
ttCard( sortedArr.forEach((ttObject) => {
return ttObject
}))
也不工作
我已經谷歌搜索並嘗試研究,但到目前為止沒有希望。 我知道最初我的嵌套地圖很糟糕,但這就是我的對象的樣子:
[
{
"class_code": "English-5-G-2-L-1911-test-teacher",
"id": 23,
"lecturer": "test teacher",
"module": "English-5",
"room": "L",
"timetable": [
{
"end_time": "9:00",
"id": 37,
"start_time": "8:00",
"weekday": "Sunday"
},
{
"end_time": "10:00",
"id": 38,
"start_time": "9:00",
"weekday": "Sunday"
},
{
"end_time": "10:00",
"id": 47,
"start_time": "9:00",
"weekday": "Monday"
},
{
"end_time": "10:00",
"id": 48,
"start_time": "9:00",
"weekday": "Tuesday"
},
{
"end_time": "11:30",
"id": 52,
"start_time": "10:30",
"weekday": "Tuesday"
},
{
"end_time": "11:30",
"id": 54,
"start_time": "10:30",
"weekday": "Thursday"
},
{
"end_time": "12:30",
"id": 58,
"start_time": "11:30",
"weekday": "Thursday"
},
{
"end_time": "14:00",
"id": 61,
"start_time": "13:00",
"weekday": "Wednesday"
}
]
}
]
您可以在輸出上使用sort
按 startTime 排列數組
.sort((a, b) => {
// These lines are so we can directly compare the times
// I would recommend to send timestamps down with your data (if possible)
var aTime = a.startTime.replace(':', '');
var bTime = b.startTime.replace(':', '');
// Sort by smallest first
return aTime - bTime;
});
我還建議過濾掉數組中的空值
使用你的例子 -
var classesArr = props.dataArray.map((classObj) => {
return classObj.timetable.map((timetableObj) => {
if (timetableObj.weekday === props.day) {
return {
lecturer: classObj.lecturer,
module: classObj.module,
room: classObj.room,
class_id: classObj.id,
timetable_id: timetableObj.id,
startTime: timetableObj.start_time,
endTime: timetableObj.end_time,
weekday: timetableObj.weekday
}
}
return null;
}).filter(x => x); // Filter out any null values
}).filter(x => x); // Filter out any null values.
// Flatten array so it is sortable/mapable
return [].concat.apply([], classesArr).sort((a, b) => {
// These lines are so we can directly compare the times
// I would recommend to send timestamps down with your data (if possible)
var aTime = a.startTime.replace(':', '');
var bTime = b.startTime.replace(':', '');
// Sort by smallest time first
return aTime - bTime;
}).map((x) => {
return ttCard(x);
})
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