map 多个值到一个属性的最佳方法

Question

我有以下对象，它们代表由一组问题及其可能的答案选项组成的调查：

{ "surveyTitle": "Survey 1", "questionText": "Question 1?", "questionId": 1, "offeredAnswerText": "Answer 1", "offeredAnswerId": 1 },
{ "surveyTitle": "Survey 1", "questionText": "Question 1?", "questionId": 1, "offeredAnswerText": "Answer 2", "offeredAnswerId": 2 },
{ "surveyTitle": "Survey 1", "questionText": "Question 2?", "questionId": 2, "offeredAnswerText": "Answer 3", "offeredAnswerId": 3 }

这是来自我桌子上的 INNER JOIN 并且它不是一个很好的 state 传递到前端。 我正在尝试修改调查 object 所以我可以先按问题分组，然后 map 他们问题的答案选项，所以它们看起来像这样：

question: { id: int, text: string, answerOptions: [] }

其中answerOption由text和id组成：

answerOption: { offeredAnswerId, offeredAnswerText }

我有以下表达式：

const questions = _.chain(rows).groupBy("id").map((question, i) => ({
        id: i,
        text: question[0].questionText,
        answerOptions: _.map(question, 'offeredAnswerText')
    })).value();

到目前为止效果很好，但我希望answerOptions数组还包括完整的answerOption object，即如上所示的 id 和文本。

我在我的项目中使用 lodash 来帮助解决这个问题。

Answer 1

您可以直接 map 想要的属性。 并取questionId而不是id进行分组。

 var rows = [{ "surveyTitle": "Survey 1", "questionText": "Question 1?", "questionId": 1, "offeredAnswerText": "Answer 1", "offeredAnswerId": 1 }, { "surveyTitle": "Survey 1", "questionText": "Question 1?", "questionId": 1, "offeredAnswerText": "Answer 2", "offeredAnswerId": 2 }, { "surveyTitle": "Survey 1", "questionText": "Question 2?", "questionId": 2, "offeredAnswerText": "Answer 3", "offeredAnswerId": 3 }], questions = _.chain(rows).groupBy("questionId").map((question, id) => ({ id, text: question[0].questionText, answerOptions: _.map(question, ({ offeredAnswerId, offeredAnswerText }) => ({ offeredAnswerId, offeredAnswerText })) })).value(); console.log(questions);

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