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back: Serve all next passings instead of only the next one

This commit is contained in:
Mattéo Delabre 2020-07-19 00:10:08 +02:00
parent 2520d03d13
commit d5362041ca
Signed by: matteo
GPG Key ID: AE3FBD02DC583ABB
1 changed files with 33 additions and 10 deletions
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43
back/data/realtime.js
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@ -1,7 +1,22 @@
const tam = require('./sources/tam');
const util = require('../util');
/**
* Comparison function between two stop passings.
*
* @param passing1 First stop passing.
* @param passing2 Second stop passing.
* @return Negative value if passing1 is sooner than passing2, positive
* otherwise, zero if they occur at the same time.
*/
const passingCompare = ({arrivalTime: time1}, {arrivalTime: time2}) => (
time1 - time2
);
// Time at which the course data needs to be updated next
let nextUpdate = null;
// Current information about courses
let currentCourses = null;
/**
@ -14,10 +29,10 @@ let currentCourses = null;
*
* - `id`: Unique identifier for the course.
* - `line`: Line number.
* - `nextStop`: Identifier of the next stop of the course.
* - `arrivalTime`: Timestamp at which the vehicle is predicted to arrive
* to the next stop.
* - `finalStop`: The final stop to which the course is headed.
* - `nextPassings`: Next passings of the vehicle, sorted by increasing
* arrival time, containing both the stop identifier (`stopId`) and the
* expected arrival timestamp (`arrivalTime`).
*
* @return Mapping from active course IDs to information about each course.
*/
@ -42,6 +57,13 @@ const getCourses = () => new Promise((res, rej) =>
if (!util.isObject(entry))
{
// End of courses information stream. Sort next stops by increasing
// arrival time in each course then save result in memory cache
for (let course of Object.values(courses))
{
course.nextPassings.sort(passingCompare);
}
currentCourses = courses;
res(currentCourses);
return;
@ -49,6 +71,7 @@ const getCourses = () => new Promise((res, rej) =>
if ('lastUpdate' in entry)
{
// Metadata header
lastUpdate = entry.lastUpdate;
nextUpdate = entry.nextUpdate;
return;
@ -57,7 +80,7 @@ const getCourses = () => new Promise((res, rej) =>
const {
course: id,
routeShortName: line,
stopId: nextStop,
stopId,
destArCode: finalStop,
} = entry;
@ -65,14 +88,14 @@ const getCourses = () => new Promise((res, rej) =>
if (!(id in courses))
{
courses[id] = {id, line, nextStop, arrivalTime, finalStop};
courses[id] = {
id, line, finalStop,
nextPassings: [{stopId, arrivalTime}],
};
}
else if (arrivalTime < courses[id].arrivalTime)
else
{
// The stop where the next passing is soonest is assumed
// to be the next stop
courses[id].nextStop = nextStop;
courses[id].arrivalTime = arrivalTime;
courses[id].nextPassings.push({stopId, arrivalTime});
}
});
});