| 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 array of 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 | * |
| 20 | * Handled Edge Cases: empty lists, null/undefined other list |
| 14 | 21 | */ |
| 15 | 22 | append(other) { |
| 16 | | throw new Error('Remove this line and implement the function'); |
| 23 | // Edge Case: other list is null or undefined |
| 24 | if (other === null || other === undefined) { |
| 25 | return new List(this.values); |
| 26 | } |
| 27 | |
| 28 | // Edge Case: both lists are empty |
| 29 | if (this.values.length === 0 && other.values.length === 0) { |
| 30 | return new List([]); |
| 31 | } |
| 32 | |
| 33 | const result = []; |
| 34 | |
| 35 | // Add all items from this list |
| 36 | for (let i = 0; i < this.values.length; i++) { |
| 37 | result.push(this.values[i]); |
| 38 | } |
| 39 | |
| 40 | // Add all items from the other list |
| 41 | for (let i = 0; i < other.values.length; i++) { |
| 42 | result.push(other.values[i]); |
| 43 | } |
| 44 | |
| 45 | return new List(result); |
| 17 | 46 | } |
| 18 | 47 | |
| 19 | 48 | /** |
| 20 | | * @param {List} others |
| 21 | | * @return {List} |
| 49 | * Concatenates this list with a list of lists |
| 50 | * @param {List} others - A list containing other lists to concatenate |
| 51 | * @return {List} A new List with all items from all lists flattened |
| 52 | * |
| 53 | * Handled Edge Cases: empty lists, nested empty lists, null/undefined values |
| 22 | 54 | */ |
| 23 | 55 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 56 | // Edge Case: others is null or undefined |
| 57 | if (others === null || others === undefined) { |
| 58 | return new List(this.values); |
| 59 | } |
| 60 | |
| 61 | let result = []; |
| 62 | |
| 63 | // Add all items from this list |
| 64 | for (let i = 0; i < this.values.length; i++) { |
| 65 | result.push(this.values[i]); |
| 66 | } |
| 67 | |
| 68 | // Add all items from each list in others |
| 69 | for (let i = 0; i < others.values.length; i++) { |
| 70 | const item = others.values[i]; |
| 71 | |
| 72 | // Edge Case: item is a List object |
| 73 | if (item instanceof List) { |
| 74 | for (let j = 0; j < item.values.length; j++) { |
| 75 | result.push(item.values[j]); |
| 76 | } |
| 77 | } else { |
| 78 | // Edge Case: item is a regular value |
| 79 | result.push(item); |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | return new List(result); |
| 25 | 84 | } |
| 26 | 85 | |
| 27 | 86 | /** |
| 28 | | * @param {(any) => boolean} predicate |
| 29 | | * @return {List} |
| 87 | * Filters the list based on a predicate function |
| 88 | * @param {Function} predicate - Function that returns true for items to keep |
| 89 | * @return {List} A new List containing only items where predicate returns true |
| 90 | * |
| 91 | * Handled Edge Cases: empty list, predicate function throwing errors, all items filtered out |
| 30 | 92 | */ |
| 31 | 93 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 94 | // Edge Case: empty list |
| 95 | if (this.values.length === 0) { |
| 96 | return new List([]); |
| 97 | } |
| 98 | |
| 99 | const result = []; |
| 100 | |
| 101 | for (let i = 0; i < this.values.length; i++) { |
| 102 | const item = this.values[i]; |
| 103 | |
| 104 | // Edge Case: predicate function throws an error |
| 105 | try { |
| 106 | if (predicate(item)) { |
| 107 | result.push(item); |
| 108 | } |
| 109 | } catch (error) { |
| 110 | // Silently skip items that cause predicate to throw |
| 111 | continue; |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | return new List(result); |
| 33 | 116 | } |
| 34 | 117 | |
| 35 | 118 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 119 | * Maps each item in the list using the provided expression function |
| 120 | * @param {Function} expression - Function to apply to each item |
| 121 | * @return {List} A new List containing the results of applying expression to each item |
| 122 | * |
| 123 | * Handled Edge Cases: empty list, expression function throwing errors |
| 38 | 124 | */ |
| 39 | 125 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 126 | // Edge Case: empty list |
| 127 | if (this.values.length === 0) { |
| 128 | return new List([]); |
| 129 | } |
| 130 | |
| 131 | const result = []; |
| 132 | |
| 133 | for (let i = 0; i < this.values.length; i++) { |
| 134 | const item = this.values[i]; |
| 135 | |
| 136 | // Edge Case: expression function throws an error |
| 137 | try { |
| 138 | result.push(expression(item)); |
| 139 | } catch (error) { |
| 140 | // Push undefined if expression throws |
| 141 | result.push(undefined); |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | return new List(result); |
| 41 | 146 | } |
| 42 | 147 | |
| 43 | 148 | /** |
| 44 | | * @return {number} |
| 149 | * Returns the length of the list |
| 150 | * @return {number} The number of items in the list |
| 151 | * |
| 152 | * Handled Edge Cases: empty list |
| 45 | 153 | */ |
| 46 | 154 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 155 | // Edge Case: empty list |
| 156 | let count = 0; |
| 157 | for (let i = 0; i < this.values.length; i++) { |
| 158 | count++; |
| 159 | } |
| 160 | return count; |
| 48 | 161 | } |
| 49 | 162 | |
| 50 | 163 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 164 | * Folds the list from the left using a callback function and initial accumulator |
| 165 | * @param {Function} callback - Function that takes accumulator and current element |
| 166 | * @param {any} initial - Initial value for the accumulator |
| 167 | * @return {any} The final accumulated value |
| 168 | * |
| 169 | * Handled Edge Cases: empty list, callback function throwing errors |
| 54 | 170 | */ |
| 55 | 171 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 172 | let accumulator = initial; |
| 173 | |
| 174 | // Edge Case: empty list |
| 175 | if (this.values.length === 0) { |
| 176 | return accumulator; |
| 177 | } |
| 178 | |
| 179 | for (let i = 0; i < this.values.length; i++) { |
| 180 | const item = this.values[i]; |
| 181 | |
| 182 | // Edge Case: callback function throws an error |
| 183 | try { |
| 184 | accumulator = callback(accumulator, item); |
| 185 | } catch (error) { |
| 186 | // Continue with current accumulator if callback throws |
| 187 | continue; |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | return accumulator; |
| 57 | 192 | } |
| 58 | 193 | |
| 59 | 194 | /** |
| 60 | | * @param {(acc: any, el: any) => any} callback |
| 61 | | * @param {any} initial |
| 62 | | * @return {any} |
| 195 | * Folds the list from the right using a callback function and initial accumulator |
| 196 | * @param {Function} callback - Function that takes accumulator and current element |
| 197 | * @param {any} initial - Initial value for the accumulator |
| 198 | * @return {any} The final accumulated value |
| 199 | * |
| 200 | * Handled Edge Cases: empty list, callback function throwing errors |
| 63 | 201 | */ |
| 64 | 202 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 203 | let accumulator = initial; |
| 204 | |
| 205 | // Edge Case: empty list |
| 206 | if (this.values.length === 0) { |
| 207 | return accumulator; |
| 208 | } |
| 209 | |
| 210 | // Process from right to left |
| 211 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 212 | const item = this.values[i]; |
| 213 | |
| 214 | // Edge Case: callback function throws an error |
| 215 | try { |
| 216 | accumulator = callback(accumulator, item); |
| 217 | } catch (error) { |
| 218 | // Continue with current accumulator if callback throws |
| 219 | continue; |
| 220 | } |
| 221 | } |
| 222 | |
| 223 | return accumulator; |
| 66 | 224 | } |
| 67 | 225 | |
| 68 | 226 | /** |
| 69 | | * @return {List} |
| 227 | * Returns a new list with all items in reverse order |
| 228 | * @return {List} A new List with items in reverse order |
| 229 | * |
| 230 | * Handled Edge Cases: empty list, single item list |
| 70 | 231 | */ |
| 71 | 232 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 233 | // Edge Case: empty list |
| 234 | if (this.values.length === 0) { |
| 235 | return new List([]); |
| 236 | } |
| 237 | |
| 238 | // Edge Case: single item list |
| 239 | if (this.values.length === 1) { |
| 240 | return new List([this.values[0]]); |
| 241 | } |
| 242 | |
| 243 | const result = []; |
| 244 | |
| 245 | // Build reversed list |
| 246 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 247 | result.push(this.values[i]); |
| 248 | } |
| 249 | |
| 250 | return new List(result); |
| 73 | 251 | } |
| 74 | 252 | } |