Pagination: don't throw on first page when totalCount=0, validate params

This commit is contained in:
Alice Gaudon 2021-04-22 11:40:27 +02:00
parent 23a11e7d60
commit 93aa8579c3
2 changed files with 55 additions and 22 deletions

View File

@ -6,11 +6,14 @@ export default class Pagination {
public readonly totalCount: number;
public constructor(page: number, perPage: number, totalCount: number) {
if (perPage <= 0) throw new Error('perPage must be >= 1');
if (totalCount < 0) throw new Error('totalCount must be >= 0');
this.page = page;
this.perPage = perPage;
this.totalCount = totalCount;
if (this.page < 1 || this.page > this.lastPage) {
if (this.page < 1 || this.page > 1 && this.page > this.lastPage) {
throw new PageNotFoundError(this.page);
}
}
@ -24,7 +27,7 @@ export default class Pagination {
}
public get lastPage(): number {
return Math.ceil(this.totalCount / this.perPage);
return Math.max(Math.ceil(this.totalCount / this.perPage), 1);
}
public previousPages(contextSize: number): number[] {

View File

@ -5,15 +5,61 @@ describe('Pagination', () => {
test('Should have correct page', () => {
expect(pagination.page).toBe(3);
});
test('Should have correct perPage', () => {
expect(pagination.perPage).toBe(5);
});
test('Should have correct totalCount', () => {
expect(pagination.totalCount).toBe(31);
});
// Parameter validation
test('Invalid perPage should throw', () => {
expect(() => {
new Pagination(1, 0, 5);
}).toThrow('perPage must be >= 1');
expect(() => {
new Pagination(1, -1, 5);
}).toThrow('perPage must be >= 1');
expect(() => {
new Pagination(1, -5, 5);
}).toThrow('perPage must be >= 1');
});
test('Invalid totalCount should throw', () => {
expect(() => {
new Pagination(1, 5, -1);
}).toThrow('totalCount must be >= 0');
expect(() => {
new Pagination(2, 5, -5);
}).toThrow('totalCount must be >= 0');
});
test('Should throw on out of bound creation attempt', () => {
expect(() => {
new Pagination(-1, 5, 15);
}).toThrow('Page -1 not found.');
expect(() => {
new Pagination(-20, 5, 15);
}).toThrow('Page -20 not found.');
expect(() => {
new Pagination(3, 5, 15);
}).not.toThrow();
expect(() => {
new Pagination(4, 5, 15);
}).toThrow('Page 4 not found.');
expect(() => {
new Pagination(20, 5, 15);
}).toThrow('Page 20 not found.');
});
test('Page 1 should not throw with totalCount=0', () => {
expect(() => {
new Pagination(1, 5, 0);
}).not.toThrow();
expect(() => {
new Pagination(2, 5, 0);
}).toThrow('Page 2 not found.');
});
test('Should calculate correct last page', () => {
expect(new Pagination(3, 5, 30).lastPage).toBe(6);
expect(new Pagination(3, 5, 31).lastPage).toBe(7);
@ -21,6 +67,8 @@ describe('Pagination', () => {
expect(new Pagination(3, 5, 34).lastPage).toBe(7);
expect(new Pagination(3, 5, 35).lastPage).toBe(7);
expect(new Pagination(3, 5, 36).lastPage).toBe(8);
expect(new Pagination(1, 5, 0).lastPage).toBe(1);
});
test('Should properly tell whether has a previous page', () => {
@ -47,24 +95,6 @@ describe('Pagination', () => {
expect(new Pagination(4, 5, 17).hasNext()).toBe(false);
});
test('Should throw on out of bound creation attempt', () => {
expect(() => {
new Pagination(-1, 5, 15);
}).toThrow('Page -1 not found.');
expect(() => {
new Pagination(-20, 5, 15);
}).toThrow('Page -20 not found.');
expect(() => {
new Pagination(3, 5, 15);
}).not.toThrow();
expect(() => {
new Pagination(4, 5, 15);
}).toThrow('Page 4 not found.');
expect(() => {
new Pagination(20, 5, 15);
}).toThrow('Page 20 not found.');
});
test('Should generate proper previous pages with context', () => {
expect(new Pagination(1, 1, 100).previousPages(1)).toStrictEqual([]);
expect(new Pagination(1, 1, 100).previousPages(2)).toStrictEqual([]);