| 4 | 4 | // |
| 5 | 5 | |
| 6 | 6 | export class List { |
| 7 | | constructor() { |
| 8 | | throw new Error('Remove this line and implement the function'); |
| 7 | /** |
| 8 | * Creates a new List instance. |
| 9 | * @param {Array} [values=[]] - Initial values for the list. |
| 10 | */ |
| 11 | constructor(values = []) { |
| 12 | this.values = values; |
| 9 | 13 | } |
| 10 | 14 | |
| 11 | 15 | /** |
| 12 | | * @param {List} other |
| 13 | | * @return {List} |
| 16 | * Appends all items from another list to the end of this list. |
| 17 | * @param {List} other - The list to append. |
| 18 | * @return {List} A new List containing all items from both lists. |
| 19 | * Handled Edge Cases: Empty lists, null/undefined other list |
| 14 | 20 | */ |
| 15 | 21 | append(other) { |
| 16 | | throw new Error('Remove this line and implement the function'); |
| 22 | // Edge Case: Handle null or undefined other list |
| 23 | if (!other) { |
| 24 | return new List(this.values); |
| 25 | } |
| 26 | |
| 27 | // Edge Case: Handle empty lists |
| 28 | const result = []; |
| 29 | for (let i = 0; i < this.values.length; i++) { |
| 30 | result.push(this.values[i]); |
| 31 | } |
| 32 | for (let i = 0; i < other.values.length; i++) { |
| 33 | result.push(other.values[i]); |
| 34 | } |
| 35 | return new List(result); |
| 17 | 36 | } |
| 18 | 37 | |
| 19 | 38 | /** |
| 20 | | * @param {List} others |
| 21 | | * @return {List} |
| 39 | * Concatenates a series of lists into one flattened list. |
| 40 | * @param {List} others - A list containing other lists to concatenate. |
| 41 | * @return {List} A new List with all items from all lists. |
| 42 | * Handled Edge Cases: Empty lists, nested empty lists |
| 22 | 43 | */ |
| 23 | 44 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 45 | const result = []; |
| 46 | |
| 47 | // Add all items from this list |
| 48 | for (let i = 0; i < this.values.length; i++) { |
| 49 | result.push(this.values[i]); |
| 50 | } |
| 51 | |
| 52 | // Add all items from each list in others |
| 53 | for (let i = 0; i < others.values.length; i++) { |
| 54 | const sublist = others.values[i]; |
| 55 | // Edge Case: Handle if sublist is not a List instance |
| 56 | if (sublist instanceof List) { |
| 57 | for (let j = 0; j < sublist.values.length; j++) { |
| 58 | result.push(sublist.values[j]); |
| 59 | } |
| 60 | } else { |
| 61 | // If it's not a List, treat it as a single value |
| 62 | result.push(sublist); |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | return new List(result); |
| 25 | 67 | } |
| 26 | 68 | |
| 27 | 69 | /** |
| 28 | | * @param {(any) => boolean} predicate |
| 29 | | * @return {List} |
| 70 | * Filters the list based on a predicate function. |
| 71 | * @param {Function} predicate - Function that returns true for items to keep. |
| 72 | * @return {List} A new List containing only items for which predicate returned true. |
| 73 | * Handled Edge Cases: Empty list, predicate function throws exception |
| 30 | 74 | */ |
| 31 | 75 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 76 | const result = []; |
| 77 | |
| 78 | // Edge Case: Handle empty list |
| 79 | if (this.values.length === 0) { |
| 80 | return new List(result); |
| 81 | } |
| 82 | |
| 83 | for (let i = 0; i < this.values.length; i++) { |
| 84 | try { |
| 85 | // Edge Case: Handle predicate function throwing exception |
| 86 | if (predicate(this.values[i])) { |
| 87 | result.push(this.values[i]); |
| 88 | } |
| 89 | } catch (e) { |
| 90 | // Silently ignore items that cause predicate to throw |
| 91 | // This follows typical filter behavior |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | return new List(result); |
| 33 | 96 | } |
| 34 | 97 | |
| 35 | 98 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 99 | * Maps each item in the list using the provided expression function. |
| 100 | * @param {Function} expression - Function to apply to each item. |
| 101 | * @return {List} A new List containing the results of applying expression to each item. |
| 102 | * Handled Edge Cases: Empty list, expression function throws exception |
| 38 | 103 | */ |
| 39 | 104 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 105 | const result = []; |
| 106 | |
| 107 | // Edge Case: Handle empty list |
| 108 | if (this.values.length === 0) { |
| 109 | return new List(result); |
| 110 | } |
| 111 | |
| 112 | for (let i = 0; i < this.values.length; i++) { |
| 113 | try { |
| 114 | // Edge Case: Handle expression function throwing exception |
| 115 | result.push(expression(this.values[i])); |
| 116 | } catch (e) { |
| 117 | // Re-throw the exception as map typically doesn't suppress errors |
| 118 | throw e; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | return new List(result); |
| 41 | 123 | } |
| 42 | 124 | |
| 43 | 125 | /** |
| 44 | | * @return {number} |
| 126 | * Returns the number of items in the list. |
| 127 | * @return {number} The count of items in the list. |
| 128 | * Handled Edge Cases: Empty list |
| 45 | 129 | */ |
| 46 | 130 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 131 | // Edge Case: Handle empty list |
| 132 | let count = 0; |
| 133 | for (let i = 0; i < this.values.length; i++) { |
| 134 | count++; |
| 135 | } |
| 136 | return count; |
| 48 | 137 | } |
| 49 | 138 | |
| 50 | 139 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 140 | * Folds (reduces) the list from the left using a callback function. |
| 141 | * @param {Function} callback - Function to apply to each item with accumulator. |
| 142 | * @param {any} initial - Initial value for the accumulator. |
| 143 | * @return {any} The final accumulated value. |
| 144 | * Handled Edge Cases: Empty list, callback function throws exception |
| 54 | 145 | */ |
| 55 | 146 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 147 | let accumulator = initial; |
| 148 | |
| 149 | // Edge Case: Handle empty list |
| 150 | if (this.values.length === 0) { |
| 151 | return accumulator; |
| 152 | } |
| 153 | |
| 154 | for (let i = 0; i < this.values.length; i++) { |
| 155 | try { |
| 156 | // Edge Case: Handle callback function throwing exception |
| 157 | accumulator = callback(accumulator, this.values[i]); |
| 158 | } catch (e) { |
| 159 | // Re-throw the exception as fold typically doesn't suppress errors |
| 160 | throw e; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | return accumulator; |
| 57 | 165 | } |
| 58 | 166 | |
| 59 | 167 | /** |
| 60 | | * @param {(acc: any, el: any) => any} callback |
| 61 | | * @param {any} initial |
| 62 | | * @return {any} |
| 168 | * Folds (reduces) the list from the right using a callback function. |
| 169 | * @param {Function} callback - Function to apply to each item with accumulator. |
| 170 | * @param {any} initial - Initial value for the accumulator. |
| 171 | * @return {any} The final accumulated value. |
| 172 | * Handled Edge Cases: Empty list, callback function throws exception |
| 63 | 173 | */ |
| 64 | 174 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 175 | let accumulator = initial; |
| 176 | |
| 177 | // Edge Case: Handle empty list |
| 178 | if (this.values.length === 0) { |
| 179 | return accumulator; |
| 180 | } |
| 181 | |
| 182 | // Process from right to left |
| 183 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 184 | try { |
| 185 | // Edge Case: Handle callback function throwing exception |
| 186 | accumulator = callback(accumulator, this.values[i]); |
| 187 | } catch (e) { |
| 188 | // Re-throw the exception as fold typically doesn't suppress errors |
| 189 | throw e; |
| 190 | } |
| 191 | } |
| 192 | |
| 193 | return accumulator; |
| 66 | 194 | } |
| 67 | 195 | |
| 68 | 196 | /** |
| 69 | | * @return {List} |
| 197 | * Returns a new list with all items in reverse order. |
| 198 | * @return {List} A new List with items in reverse order. |
| 199 | * Handled Edge Cases: Empty list |
| 70 | 200 | */ |
| 71 | 201 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 202 | const result = []; |
| 203 | |
| 204 | // Edge Case: Handle empty list |
| 205 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 206 | result.push(this.values[i]); |
| 207 | } |
| 208 | |
| 209 | return new List(result); |
| 73 | 210 | } |
| 74 | 211 | } |