Change default index type to zero-based

package.json

@@ -55,6 +55,7 @@
     "eslint-plugin-jest": "^26.5.3",
     "eslint-plugin-prettier": "^4.1.0",
     "jest": "^28.1.2",
+    "jest-environment-jsdom": "^29.6.1",
     "prettier": "^2.7.1",
     "ts-jest": "^28.0.5",
     "typescript": "^4.7.4"

src/__test__/pagination-with-one-based-index-type.test.ts

@@ -1,18 +1,22 @@
-import { calculatePagination } from '../index'
+import { calculatePagination, IndexType } from '../index'
 
 it('should return no pagination if not enough items are given', () => {
   const page = 1
   const size = 5
   const total = 2
-  const pagination = calculatePagination(page, size, total)
+  const pagination = calculatePagination(page, size, total, {
+    indexType: IndexType.ONE_BASED,
+  })
 
   expect(pagination).toBeNull()
 })
 it('should return only a few pages', () => {
   const page = 2
   const size = 5
   const total = 15
-  const pagination = calculatePagination(page, size, total)
+  const pagination = calculatePagination(page, size, total, {
+    indexType: IndexType.ONE_BASED,
+  })
 
   expect(pagination).not.toBeNull()
   expect(pagination?.pages).toHaveLength(3)
@@ -33,6 +37,7 @@ it('should return the maximum number of pages', () => {
   const total = 50
   const maxPages = 5
   const pagination = calculatePagination(page, size, total, {
+    indexType: IndexType.ONE_BASED,
     maxPages: maxPages,
   })
 
@@ -59,7 +64,9 @@ it('should disable the previous link', () => {
   const page = 1
   const size = 5
   const total = 10
-  const pagination = calculatePagination(page, size, total)
+  const pagination = calculatePagination(page, size, total, {
+    indexType: IndexType.ONE_BASED,
+  })
 
   expect(pagination).not.toBeNull()
 
@@ -76,7 +83,9 @@ it('should disable the next link', () => {
   const page = 2
   const size = 5
   const total = 10
-  const pagination = calculatePagination(page, size, total)
+  const pagination = calculatePagination(page, size, total, {
+    indexType: IndexType.ONE_BASED,
+  })
 
   expect(pagination).not.toBeNull()
 

src/index.ts

@@ -48,14 +48,21 @@ const calculateVisiblePages = (
   return pages
 }
 
+type CalculatePaginationConfig = {
+  indexType: IndexType
+  maxPages: number
+}
+
+const defaultCalculatePaginationConfig: CalculatePaginationConfig = {
+  indexType: IndexType.ZERO_BASED,
+  maxPages: 5,
+}
+
 const calculatePagination = (
   page: number,
   size: number,
   total: number,
-  config?: {
-    indexType?: IndexType
-    maxPages?: number
-  }
+  config?: Partial<CalculatePaginationConfig>
 ): {
   previous: {
     indexNumber: number
@@ -71,13 +78,15 @@ const calculatePagination = (
     isCurrent: boolean
   }[]
 } | null => {
+  const { indexType, maxPages } = {
+    ...defaultCalculatePaginationConfig,
+    ...config,
+  }
+
   if (total <= size) {
     return null
   }
 
-  const indexType = config?.indexType ?? IndexType.ONE_BASED
-  const maxPages = config?.maxPages ?? 5
-
   const firstPage = indexType === IndexType.ZERO_BASED ? 0 : 1
   const lastPage = Math.ceil(total / size) + (firstPage - 1)
   const isCurrentTheFirstPage = page === firstPage