Merge pull request #41 from StratoKit/sort-falsyBool-with-cursor

fix bug when sorting falsyBool + cursor

Author: wmertens

src/EventSourcingDB/EventSourcingDB.js

@@ -697,7 +697,6 @@ class EventSourcingDB extends EventEmitter {
 			}
 		}
 		return lastV
-		/* eslint-enable no-await-in-loop */
 	}
 
 	async _preprocessor(cache, event, isMainEvent) {

src/JsonModel/JM-search.test.js

@@ -252,6 +252,56 @@ describe('search cursor', () => {
 			total: 10,
 		})
 	})
+
+	test('search with sort, cursor, limit - limit < total, some sorted values = falsyBool', async () => {
+		const totalCount = await m.count()
+		const falsyBoolFalseCount = await m.count({x2: false})
+		const falsyBoolTrueCount = await m.count({x2: true})
+
+		const pageCount = falsyBoolTrueCount + 1
+		// to make sure there are results on page2
+		expect(falsyBoolFalseCount - pageCount).toBeTruthy()
+
+		const searchOptions = {
+			// true first
+			sort: {x2: -1},
+			limit: pageCount,
+			cols: ['id', 'x2'],
+		}
+		const page1 = await m.search({}, searchOptions)
+
+		expect(page1).toEqual({
+			cursor: '!_N~1',
+			items: [
+				{id: 2, x2: 1},
+				{id: 4, x2: 1},
+				{id: 6, x2: 1},
+				{id: 8, x2: 1},
+				{id: 10, x2: 1},
+				{id: 12, x2: 1},
+				{id: 14, x2: 1},
+				{id: 1},
+			],
+			prevCursor: '!!1~2',
+			total: 14,
+		})
+
+		const page2Count = await m.count(
+			{},
+			{...searchOptions, cursor: page1.cursor}
+		)
+		const remainingAfterPage1 = totalCount - pageCount
+		expect(page2Count).toEqual(
+			remainingAfterPage1 < pageCount ? remainingAfterPage1 : pageCount
+		)
+		const page2 = await m.search({}, {...searchOptions, cursor: page1.cursor})
+		expect(page2).toEqual({
+			cursor: undefined,
+			items: [{id: 3}, {id: 5}, {id: 7}, {id: 9}, {id: 11}, {id: 13}],
+			prevCursor: '!!_N~3',
+			total: 14,
+		})
+	})
 })
 
 test('search itemsOnly', async () => {

src/JsonModel/JsonModel.js

@@ -394,9 +394,15 @@ class JsonModelImpl {
 			cursorQ = `${cursorColAliases[len]}${getDir(len)}?`
 			cursorArgs = [cursorVals[len]] // ID added at first
 			for (let i = len - 1; i >= 0; i--) {
-				cursorQ =
-					`(${cursorColAliases[i]}${getDir(i)}=?` +
-					` AND (${cursorColAliases[i]}!=? OR ${cursorQ}))`
+				const colAlias = cursorColAliases[i]
+				const isFalsyBool = Object.values(this.columns).find(
+					c => c.alias === colAlias
+				).falsyBool
+				cursorQ = isFalsyBool
+					? `(COALESCE(${colAlias}, 0)${getDir(i)}=COALESCE(?, 0)` +
+						` AND (COALESCE(${colAlias},0)!=COALESCE(?, 0) OR ${cursorQ}))`
+					: `(${cursorColAliases[i]}${getDir(i)}=?` +
+						` AND (${cursorColAliases[i]}!=? OR ${cursorQ}))`
 				const val = cursorVals[i]
 				cursorArgs.unshift(val, val)
 			}