如何更新 JSON 數組中的屬性 - Ramdajs

Question

輸入：

[{
    message: 'A1 Message, B1 Message, C1 Message'
}, {
    message: 'A1 Message, B1 Message'
}];

Output：

[{
    message: 'C1 Message'
}, {
    message: null
}];

識別特定消息“C1”（子字符串）並更新字符串或在對象數組中設置為 null

嘗試了以下：

var input = [{
    id: 1,
    message: 'A1 Message, B1 Message, C1 Message'
}, {
    id: 2,
    message: 'A1 Message, B1 Message'
}];

var updateMessage = (obj) => {
    var C1Message = R.pipe(
        R.prop('message'),
        R.splitAt(obj.message.indexOf('C1')),
        R.last
    )(obj);
    return R.assoc('message', C1Message, obj);
}

var updateArray = R.map(R.when(R.pipe(R.prop('message'), R.includes('C1')), updateMessage));
var output = updateArray(input);
console.log(output);

如何使用ifElse將第二條object消息設置為null？

Answer 1

你可以進化數組中的每個 object。 對於每條message ，請嘗試匹配您需要的消息格式。 如果未找到匹配項（空數組），則返回null 。 如果找到匹配項， R.match的結果中取出第一個元素：

 const { map, evolve, pipe, match, ifElse, isEmpty, always, head } = R const fn = map(evolve({ message: pipe( match(/C1[^,]+/), // match C1 message ifElse(isEmpty, always(null), // if empty assign null head // if not take the 1st element ) ) })) const data = [{ message: 'A1 Message, B1 Message, C1 Message' }, { message: 'A1 Message, B1 Message' }]; const result = fn(data) console.log(result)

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動態使用 - 將 RegExp 作為參數傳遞：

 const { map, evolve, pipe, match, ifElse, isEmpty, always, join } = R const fn = regexp => map(evolve({ message: pipe( match(regexp), // match a RegExp ifElse(isEmpty, always(null), // if empty assign null join(', ') // if not convert to a string ) ) })) const data = [{ message: 'A1 Message, B1 Message, C1 Message 1, C1 Message 2' }, { message: 'A1 Message, B1 Message' }]; const result = fn(/C1[^,]+/g)(data) console.log(result)

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