fix: handle zeros in paginated meta info correctly (#82)

Co-authored-by: Anbraten <anton@ju60.de>

src/utils.ts

@@ -32,5 +32,10 @@ export type ServiceModel<
 
 export function isPaginated<T>(response: T | T[] | Paginated<T>): response is Paginated<T> {
   const { total, limit, skip, data } = response as Paginated<T>;
-  return total !== undefined && limit !== undefined && skip !== undefined && data !== undefined && Array.isArray(data);
+  return (
+    typeof total === 'number' &&
+    typeof limit === 'number' &&
+    (typeof skip === 'number' || typeof skip === 'string') &&
+    Array.isArray(data)
+  );
 }

test/utils.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest';
 
-import { getId, PotentialIds } from '~/utils';
+import { getId, isPaginated, PotentialIds } from '~/utils';
 
 describe('getId()', () => {
   it('should return "id" property from item', () => {
@@ -27,3 +27,93 @@ describe('getId()', () => {
     expect(() => getId(item as PotentialIds)).toThrow('Unable to retrieve id from item');
   });
 });
+
+describe('isPaginated()', () => {
+  it('should return true when total, limit, skip and data array are present', () => {
+    // given
+    const response = {
+      total: 100,
+      limit: 10,
+      skip: 20,
+      data: [],
+    };
+
+    // then
+    expect(isPaginated<typeof response>(response)).toBe(true);
+  });
+
+  it('should return true when total, limit and skip is "0"', () => {
+    // given
+    const response = {
+      total: 0,
+      limit: 0,
+      skip: 0,
+      data: [],
+    };
+
+    // then
+    expect(isPaginated<typeof response>(response)).toBe(true);
+  });
+
+  it('should return true when skip is a string', () => {
+    // given
+    const response = {
+      total: 100,
+      limit: 10,
+      skip: '20',
+      data: [],
+    };
+
+    // then
+    expect(isPaginated<typeof response>(response)).toBe(true);
+  });
+
+  it('should return false when total is missing', () => {
+    // given
+    const response = {
+      limit: 10,
+      skip: 20,
+      data: [],
+    };
+
+    // then
+    expect(isPaginated<typeof response>(response)).toBe(false);
+  });
+
+  it('should return false when limit is missing', () => {
+    // given
+    const response = {
+      total: 100,
+      skip: 20,
+      data: [],
+    };
+
+    // then
+    expect(isPaginated<typeof response>(response)).toBe(false);
+  });
+
+  it('should return false when skip is missing', () => {
+    // given
+    const response = {
+      total: 100,
+      limit: 10,
+      data: [],
+    };
+
+    // then
+    expect(isPaginated<typeof response>(response)).toBe(false);
+  });
+
+  it('should return false when data is no array', () => {
+    // given
+    const response = {
+      total: 100,
+      limit: 10,
+      skip: 20,
+      data: {},
+    };
+
+    // then
+    expect(isPaginated<typeof response>(response)).toBe(false);
+  });
+});