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  1. var data = [
  2. 	{'city': 'Джакарта', 'country': 'Индонезия', 'population': 30539, 'area': 3225, 'density': 9500 },
  3. 	{'city': 'Каир', 'country': 'Египет', 'population': 25600, 'area': 1761, 'density': 15105 },
  4. 	{'city': 'Карачи', 'country': 'Пакистан', 'population': 25423, 'area': 945, 'density': 26902 },
  5. 	{'city': 'Токио', 'country': 'Япония', 'population': 37843, 'area': 8547, 'density': 4400 },
  6. ];
  7.  
  8. function sortTable(sortByField, sortType, limit) {
  9. 	var result = data.sort(getSortCallbackFor(sortByField, sortType));
  10.  
  11. 	if (!Number.isInteger(limit) || limit < 0) {
  12. 		return result;
  13. 	}
  14.  
  15. 	return result.slice(0, limit);
  16. }
  17.  
  18. function getSortCallbackFor(field, order) {
  19. 	var resultCallback;
  20. 	if (['city', 'country'].indexOf(field) >= 0) {
  21. 		if (order === 'ASC') {
  22. 			resultCallback = function(a, b) {
  23. 				return a[field].localeCompare(b[field]);
  24. 			}
  25. 		} else if (order === 'DESC') {
  26. 			resultCallback = function(a, b) {
  27. 				return b[field].localeCompare(a[field]);
  28. 			}
  29. 		} else {
  30. 			throw new Error('Invalid order');
  31. 		}
  32. 	} else if (['population', 'area', 'density'].indexOf(field) >= 0) {
  33. 		if (order === 'ASC') {
  34. 			resultCallback = function(a, b) {
  35. 				return a[field] - b[field];
  36. 			}
  37. 		} else if (order === 'DESC') {
  38. 			resultCallback = function(a, b) {
  39. 				return b[field] - a[field];
  40. 			}
  41. 		} else {
  42. 			throw new Error('Invalid order');
  43. 		}
  44. 	} else {
  45. 		throw new Error('Invalid field');
  46. 	}
  47.  
  48. 	return resultCallback;
  49. }
  50.  
  51. // Тесты
  52. var tableSorted1 = sortTable('population', 'DESC', 3);
  53. console.log(tableSorted1.length === 3);
  54. console.log(tableSorted1[0].city === 'Токио');
  55. console.log(tableSorted1[1].city === 'Джакарта');
  56. console.log(tableSorted1[2].city === 'Каир');
  57.  
  58. var tableSorted2 = sortTable('country', 'ASC');
  59. console.log(tableSorted2.length === 4);
  60. console.log(tableSorted2[0].country === 'Египет');
  61. console.log(tableSorted2[1].country === 'Индонезия');
  62. console.log(tableSorted2[2].country === 'Пакистан');
  63. console.log(tableSorted2[3].country === 'Япония');
  64.  
Success #stdin #stdout 0.06s 21168KB
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https://ideone.com/ntoBFC
language:
Node.js (node 11.12.0)
created:
8 years ago
visibility:
public

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