Show adjacent chunks when translating

server/router/translate/index.js

@@ -1,4 +1,5 @@
 const express = require('express')
+const { Op } = require("sequelize")
 
 module.exports = function (options) {
     const db = options.db;
@@ -74,18 +75,28 @@ module.exports = function (options) {
             })
         })
 
-    router.route('/:id/chapter/:chapterId/t/:chunkId')
+    router.route('/:id/chapter/:chapterId/t/:chunkIndex')
         .get(function(request, response, next) {
-            db.Chunk.findByPk(request.params.chunkId, {
+            const previousIndex = Number(request.params.chunkIndex)-1
+            const nextIndex = Number(request.params.chunkIndex)+1
+            db.Chunk.findAll({
+                where: {
+                    chapterId: request.params.chapterId,
+                    index: {
+                        [Op.between]: [
+                            previousIndex, 
+                            nextIndex
+                        ],
+                    }
+                },
+                limit: 3,
                 include: [
                     {
                         association: db.Chunk.Translation
                     },
                     {
                         association: db.Chunk.Chapter,
-                        where: {
-                            id: request.params.chapterId
-                        },
+                        required: true,
                         include: [
                             {
                                 association: db.Chapter.Entry,
@@ -106,12 +117,15 @@ module.exports = function (options) {
                         ]
                     }
                 ]
-            }).then(chunk => {
-                if (chunk) {
+            }).then(chunks => {
+                if (chunks.length > 0) {
+                    const chunk = chunks.find(chunk => chunk.index == Number(request.params.chunkIndex))
                     response.display("translate-chunk", {
                         user: request.user,
                         pageTitle: `Translate ${chunk.chapter.entry.name}`,
-                        chunk: chunk 
+                        chunk: chunk,
+                        previousChunk: chunks.find(chunk => chunk.index == previousIndex),
+                        nextChunk: chunks.find(chunk => chunk.index == nextIndex)
                     })
                 } else {
                     next()