json-server/test/server/utils.js

const assert = require('assert')
const utils = require('../../src/server/utils')

describe('utils', () => {
  describe('getPage', () => {
    const array = [1, 2, 3, 4, 5]
    const perPage = 2

    it('should return first page', () => {
      assert.deepEqual(
        utils.getPage(array, 1, perPage),
        {
          items: [1, 2],
          current: 1,
          first: 1,
          next: 2,
          last: 3
        }
      )
    })

    it('should return second page', () => {
      assert.deepEqual(
        utils.getPage(array, 2, perPage),
        {
          items: [3, 4],
          current: 2,
          first: 1,
          prev: 1,
          next: 3,
          last: 3
        }
      )
    })

    it('should return third page (last)', () => {
      assert.deepEqual(
        utils.getPage(array, 3, perPage),
        {
          items: [5],
          current: 3,
          first: 1,
          prev: 2,
          last: 3
        }
      )
    })

    it('should return an empty array if page is greater than the last page', () => {
      assert.deepEqual(
        utils.getPage(array, 99, perPage),
        {
          items: []
        }
      )
    })

    it('should return the array if perPage is greater than the array size', () => {
      assert.deepEqual(
        utils.getPage(array, 1, 99),
        {
          items: array
        }
      )
    })

    it('should return an empty array if the array is empty', () => {
      assert.deepEqual(
        utils.getPage([], 1, 1),
        {
          items: []
        }
      )
    })
  })
})