[英]Struggling to refactor this using Ramda.js, here is how far I got
我正在学习Ramda.js。 我试图使用Ramda重构的函数如下。 它调用函数firestore
数据库方法来获取一些数据。 但是firestore在snapshot
方法中返回数据,我们需要调用.data()
。 根据结果,我想构建不同的响应。
愿你喜欢这里的思考过程
const queryForUsersQuizResults = async (request, response) => {
try {
const snapshot = await firestore
.collection("quizResults")
.doc(request.user.uid)
.collection("courses_chapters")
.doc(request.params.courseId + "_" + request.params.chapterId)
.get();
let data = snapshot.data();
if (!data) {
data = {
message: "result not found for this user for this course and chapter"
};
}
return response.send(data);
} catch (error) {
return response.status(500).send(error);
}
}
......这就是我能够重构的,我希望看到更好/其他方式(我不确定这是否有效)。 我正在努力使用sendResult
方法。
//get user id
export const getUserId = pathOr('', ['user', 'uid']);
// get chapter id
export const getChapterId = concat(pathOr('', ['params', 'courseId']), '_', pathOr('', ['params', 'chapterId']));
//queryQuizResult
export const query = curry(async (firestore, request) => {
return tryCatch(() =>
firestore
.collection("quizResults")
.doc(getUserId(request))
.collection("courses_chapters")
.doc(getChapterId(request))
.get(), F)();
});
//Receives "response" object and calls response.status with the value passed to the new status function
export const status = invoker(1, "status");
//Receives "response" object and calls response.send witht he value passed to the new send function
export const send = invoker(1, "send");
//Create {"message",Your_Error} object
export const constructError = objOf('message');
//Returns JSON from Firestore's snapshot object
export const getDataFromSnapshot = (snapshot) => snapshot.data();
//Actual error message
const QUIZ_RESULTS_NOT_FOUND = "Quiz results not found for this user for this course and chapter";
//Returns error message
export const quizResultsNotFoundError = constructError(QUIZ_RESULTS_NOT_FOUND);
//Receives "response" object and calls response.status and then respose.send
export const sendError = pipe(
status(401),
send(quizResultsNotFoundError)
);
//Sends valid result //IS there any better way of doing this?
export const sendResult = (snapshot, response) => {
const data = getDataFromSnapshot(snapshot);
response.send(data); //Especially this, I wanted to use the "send" method and pipe things
}
//Main Method
export const queryForUsersQuizResults = async (firestore, request, response) => {
const snapshot = await query(firestore, request);
snapshot ? sendResult(snapshot, response) :sendError(response);
}
这是我看到的移动部件。 这只是编写程序的众多可能方式之一 -
const tryCatch = f =>
new Promise
( (resolve, reject) =>
{ try { resolve (f ()) }
catch (err) { reject (err) }
}
)
const handleSuccess = res => data =>
res .send (data)
const handleError = res => err =>
res .status (500) .send (err)
const getSnapshot = (uid, docid) =>
firestore
.collection ("quizResults")
.doc (uid)
.collection ("courses_chapters")
.doc (docid)
.get ()
.data ()
const queryForUsersQuizResults = (req, res) =>
tryCatch
( () =>
getSnapshot
( req.user.uid
, req.params.courseId + "_" + req.params.chapterId
)
)
.catch
( _ => Promise .reject (Error ("result not found for this user for this course and chapter"))
)
const main = (req, res) =>
queryForUsersQuizResults (req, res)
.then
( handleSuccess (res)
, handleError (res)
)
这是一个展示行动概念的工作演示 -
const DB = { 1: "ant" , 2: "bear" , 3: "cuttlefish" } const queryForUsersQuizResults = (id = 0) => { if (DB[id] === undefined) throw Error (`no record for id: ${id}`) else return DB[id] } const tryCatch = f => { try { return Promise .resolve (f ()) } catch (err) { return Promise .reject (err) } } const fakeResponse = (status = 200) => ({ send: data => console .log ("=>", status, data) , status: n => fakeResponse (n) }) const demo = (req, res) => tryCatch (() => queryForUsersQuizResults (req.params.uid)) .then ( data => res .send (data) , err => res .status (500) .send (err) ) demo ( { params: { uid: 1 } } , fakeResponse () ) // => 200 ant demo ( { params: { uid: 2 } } , fakeResponse () ) // => 200 bear demo ( { params: { uid: 3 } } , fakeResponse () ) // => 200 cuttlefish demo ( { params: { uid: 4 } } , fakeResponse () ) // => 500 Error: no record for id: 4
我也认为你已经很好,如果你真的想使用合成,它可能是这样的:
export const sendResult = (snapshot, response) =>
pipe(getDataFromSnapshot, flip(send)(response))
(snapshot);
您需要使用flip
因为在管道定义时getDataFromSnapshot(snapshot)
没有getDataFromSnapshot(snapshot)
的结果,但是您已经拥有了持有send
方法实现的对象。
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