Add pageCount check, add getAdjacentIndexes

src/utils/page.test.js

@@ -3,8 +3,9 @@ import {
   getNextPageIndexInfinte,
   getPrevPageIndexLimited,
   getPrevPageIndexInfinte,
-  getPageIndex
-} from './page.js';
+  getPageIndex,
+  getAdjacentIndexes
+} from './page.js'
 
 describe('getNextPageIndexLimited', () => {
   it('returns next page index as expected', () => {
@@ -16,10 +17,17 @@ describe('getNextPageIndexLimited', () => {
       { currentPageIndex: 7, pagesCount: 3, expected: 2 },
     ]
     testCases.forEach(({ currentPageIndex, pagesCount, expected }) => {
-      expect(getNextPageIndexLimited(currentPageIndex, pagesCount)).toBe(expected);
-    });
-  });
-});
+      expect(getNextPageIndexLimited(currentPageIndex, pagesCount)).toBe(expected)
+    })
+  })
+  it('throws error if pagesCount is less than 1', () => {
+    const currentPageIndex = 5
+    const pagesCount = 0
+    expect(
+      () => getNextPageIndexLimited(currentPageIndex, pagesCount)
+    ).toThrowError('pagesCount must be at least 1')
+  })
+})
 
 describe('getNextPageIndexInfinte', () => {
   it('returns next page index as expected', () => {
@@ -31,10 +39,17 @@ describe('getNextPageIndexInfinte', () => {
       { currentPageIndex: 7, pagesCount: 3, expected: 0 },
     ]
     testCases.forEach(({ currentPageIndex, pagesCount, expected }) => {
-      expect(getNextPageIndexInfinte(currentPageIndex, pagesCount)).toBe(expected);
-    });
-  });
-});
+      expect(getNextPageIndexInfinte(currentPageIndex, pagesCount)).toBe(expected)
+    })
+  })
+  it('throws error if pagesCount is less than 1', () => {
+    const currentPageIndex = 5
+    const pagesCount = 0
+    expect(
+      () => getNextPageIndexInfinte(currentPageIndex, pagesCount)
+    ).toThrowError('pagesCount must be at least 1')
+  })
+})
 
 describe('getPrevPageIndexLimited', () => {
   it('returns prev page index as expected', () => {
@@ -46,10 +61,17 @@ describe('getPrevPageIndexLimited', () => {
       { currentPageIndex: 7, pagesCount: 3, expected: 2 },
     ]
     testCases.forEach(({ currentPageIndex, pagesCount, expected }) => {
-      expect(getPrevPageIndexLimited(currentPageIndex, pagesCount)).toBe(expected);
-    });
-  });
-});
+      expect(getPrevPageIndexLimited(currentPageIndex, pagesCount)).toBe(expected)
+    })
+  })
+  it('throws error if pagesCount is less than 1', () => {
+    const currentPageIndex = 5
+    const pagesCount = 0
+    expect(
+      () => getPrevPageIndexLimited(currentPageIndex, pagesCount)
+    ).toThrowError('pagesCount must be at least 1')
+  })
+})
 
 describe('getPrevPageIndexInfinte', () => {
   it('returns prev page index as expected', () => {
@@ -61,10 +83,17 @@ describe('getPrevPageIndexInfinte', () => {
       { currentPageIndex: 7, pagesCount: 3, expected: 1 },
     ]
     testCases.forEach(({ currentPageIndex, pagesCount, expected }) => {
-      expect(getPrevPageIndexInfinte(currentPageIndex, pagesCount)).toBe(expected);
-    });
-  });
-});
+      expect(getPrevPageIndexInfinte(currentPageIndex, pagesCount)).toBe(expected)
+    })
+  })
+  it('throws error if pagesCount is less than 1', () => {
+    const currentPageIndex = 5
+    const pagesCount = 0
+    expect(
+      () => getPrevPageIndexInfinte(currentPageIndex, pagesCount)
+    ).toThrowError('pagesCount must be at least 1')
+  })
+})
 
 describe('getPageIndex', () => {
   it('returns normalized page index as expected', () => {
@@ -76,7 +105,51 @@ describe('getPageIndex', () => {
       { pageIndex: 7, pagesCount: 3, expected: 2 },
     ]
     testCases.forEach(({ pageIndex, pagesCount, expected }) => {
-      expect(getPageIndex(pageIndex, pagesCount)).toBe(expected);
-    });
-  });
-});
+      expect(getPageIndex(pageIndex, pagesCount)).toBe(expected)
+    })
+  })
+  it('throws error if pagesCount is less than 1', () => {
+    const pageIndex = 5
+    const pagesCount = 0
+    expect(
+      () => getPageIndex(pageIndex, pagesCount)
+    ).toThrowError('pagesCount must be at least 1')
+  })
+})
+
+describe('getAdjacentIndexes', () => {
+  it('returns indexes as expected if infinite', () => {
+    const testCases = [
+      { pageIndex: 0, pagesCount: 1, expected: [0] },
+      { pageIndex: -5, pagesCount: 10, expected: [0, 1, 9] },
+      { pageIndex: 0, pagesCount: 10, expected: [0, 1, 9] },
+      { pageIndex: 5, pagesCount: 10, expected: [4, 5, 6] },
+      { pageIndex: 9, pagesCount: 10, expected: [0, 8, 9] },
+      { pageIndex: 15, pagesCount: 10, expected: [0, 8, 9] },
+    ]
+    testCases.forEach(({ pageIndex, pagesCount, expected }) => {
+      expect(getAdjacentIndexes(pageIndex, pagesCount, true)).toEqual(expected)
+    })
+  })
+  it('returns indexes as expected if not infinite', () => {
+    const testCases = [
+      { pageIndex: 0, pagesCount: 1, expected: [0] },
+      { pageIndex: -5, pagesCount: 10, expected: [0, 1] },
+      { pageIndex: 0, pagesCount: 10, expected: [0, 1] },
+      { pageIndex: 5, pagesCount: 10, expected: [4, 5, 6] },
+      { pageIndex: 9, pagesCount: 10, expected: [8, 9] },
+      { pageIndex: 15, pagesCount: 10, expected: [8, 9] },
+    ]
+    testCases.forEach(({ pageIndex, pagesCount, expected }) => {
+      expect(getAdjacentIndexes(pageIndex, pagesCount, false)).toEqual(expected)
+    })
+  })
+  it('throws error if pagesCount is less than 1', () => {
+    const pageIndex = 5
+    const pagesCount = 0
+    const infinite = true
+    expect(
+      () => getAdjacentIndexes(pageIndex, pagesCount, infinite)
+    ).toThrowError('pagesCount must be at least 1')
+  })
+})