filter doesn't throw an error when all data is filtered out

nshiab · Feb 27, 2025 · e13647b · e13647b
1 parent ff1422a
commit e13647b
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Showing 2 changed files with 36 additions and 23 deletions.
diff --git a/src/helpers/convertForJS.ts b/src/helpers/convertForJS.ts
@@ -3,30 +3,32 @@ export default function convertForJS(rows: {
 }[], types: {
   [key: string]: string;
 }) {
-  const firstObjectKeys = Object.keys(rows[0]);
-  for (const key of Object.keys(types)) {
-    if (!firstObjectKeys.includes(key)) {
-      continue;
-    }
-    if (types[key] === "DATE") {
-      for (const row of rows) {
-        row[key] = row[key] === null
-          ? null
-          : new Date(`${row[key]}T00:00:00.000Z`);
-      }
-    } else if (types[key] === "TIMESTAMP") {
-      for (const row of rows) {
-        row[key] = row[key] === null
-          ? null
-          : new Date((row[key] as string).replace(" ", "T") + "Z");
-      }
-    } else if (types[key] === "BIGINT" || types[key] === "HUGEINT") {
-      for (const row of rows) {
-        row[key] = row[key] === null ? null : Number(row[key]);
+  if (rows[0] !== undefined) {
+    const firstObjectKeys = Object.keys(rows[0]);
+    for (const key of Object.keys(types)) {
+      if (!firstObjectKeys.includes(key)) {
+        continue;
       }
-    } else if (types[key] === "GEOMETRY") {
-      for (const row of rows) {
-        row[key] = row[key] === null ? null : "<Geometry>";
+      if (types[key] === "DATE") {
+        for (const row of rows) {
+          row[key] = row[key] === null
+            ? null
+            : new Date(`${row[key]}T00:00:00.000Z`);
+        }
+      } else if (types[key] === "TIMESTAMP") {
+        for (const row of rows) {
+          row[key] = row[key] === null
+            ? null
+            : new Date((row[key] as string).replace(" ", "T") + "Z");
+        }
+      } else if (types[key] === "BIGINT" || types[key] === "HUGEINT") {
+        for (const row of rows) {
+          row[key] = row[key] === null ? null : Number(row[key]);
+        }
+      } else if (types[key] === "GEOMETRY") {
+        for (const row of rows) {
+          row[key] = row[key] === null ? null : "<Geometry>";
+        }
       }
     }
   }

diff --git a/test/unit/methods/filter.test.ts b/test/unit/methods/filter.test.ts
@@ -245,3 +245,14 @@ Deno.test("should filter the rows based on booleans", async () => {
   assertEquals(data, [{ name: "Nael", value: true }]);
   await sdb.done();
 });
+
+Deno.test("should not throw an error when all data has been filtered out", async () => {
+  const sdb = new SimpleDB();
+  const table = sdb.newTable("data");
+  await table.loadData(["test/data/files/employees.csv"]);
+  await table.filter(`Name = 'Nael'`);
+  const data = await table.getData();
+
+  assertEquals(data, []);
+  await sdb.done();
+});