| 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 |
| 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 another list to this list |
| 17 | * @param {List} other - The list to append |
| 18 | * @return {List} A new list containing all elements 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: Handle null or undefined other parameter |
| 24 | if (!other) { |
| 25 | return new List(this.values); |
| 26 | } |
| 27 | |
| 28 | // Edge Case: Handle when this list is empty |
| 29 | if (this.length() === 0) { |
| 30 | return new List(other.values); |
| 31 | } |
| 32 | |
| 33 | // Edge Case: Handle when other list is empty |
| 34 | if (other.length() === 0) { |
| 35 | return new List(this.values); |
| 36 | } |
| 37 | |
| 38 | return new List([...this.values, ...other.values]); |
| 17 | 39 | } |
| 18 | 40 | |
| 19 | 41 | /** |
| 20 | | * @param {List} others |
| 21 | | * @return {List} |
| 42 | * Concatenates multiple lists into one |
| 43 | * @param {List} others - A list of lists to concatenate |
| 44 | * @return {List} A new list with all elements from all lists flattened |
| 45 | * |
| 46 | * Handled Edge Cases: Empty lists, nested empty lists, null/undefined others |
| 22 | 47 | */ |
| 23 | 48 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 49 | // Edge Case: Handle null or undefined others parameter |
| 50 | if (!others) { |
| 51 | return new List(this.values); |
| 52 | } |
| 53 | |
| 54 | let result = [...this.values]; |
| 55 | |
| 56 | // Edge Case: Handle empty others list |
| 57 | if (others.length() === 0) { |
| 58 | return new List(result); |
| 59 | } |
| 60 | |
| 61 | for (let i = 0; i < others.length(); i++) { |
| 62 | const list = others.values[i]; |
| 63 | // Edge Case: Handle if an element in others is not a List |
| 64 | if (list && Array.isArray(list.values)) { |
| 65 | result = [...result, ...list.values]; |
| 66 | } |
| 67 | } |
| 68 | |
| 69 | return new List(result); |
| 25 | 70 | } |
| 26 | 71 | |
| 27 | 72 | /** |
| 28 | | * @param {(any) => boolean} predicate |
| 29 | | * @return {List} |
| 73 | * Filters the list based on a predicate function |
| 74 | * @param {(any) => boolean} predicate - Function to test each element |
| 75 | * @return {List} A new list containing only elements that pass the predicate |
| 76 | * |
| 77 | * Handled Edge Cases: Empty list, null/undefined predicate, predicate throwing errors |
| 30 | 78 | */ |
| 31 | 79 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 80 | // Edge Case: Handle null or undefined predicate |
| 81 | if (typeof predicate !== 'function') { |
| 82 | return new List([]); |
| 83 | } |
| 84 | |
| 85 | // Edge Case: Handle empty list |
| 86 | if (this.length() === 0) { |
| 87 | return new List([]); |
| 88 | } |
| 89 | |
| 90 | const result = []; |
| 91 | for (let i = 0; i < this.values.length; i++) { |
| 92 | try { |
| 93 | // Edge Case: Handle predicate function throwing errors |
| 94 | if (predicate(this.values[i])) { |
| 95 | result.push(this.values[i]); |
| 96 | } |
| 97 | } catch (e) { |
| 98 | // Silently skip elements that cause predicate to throw |
| 99 | continue; |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | return new List(result); |
| 33 | 104 | } |
| 34 | 105 | |
| 35 | 106 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 107 | * Maps each element using a provided function |
| 108 | * @param {(any) => any} expression - Function to transform each element |
| 109 | * @return {List} A new list with transformed elements |
| 110 | * |
| 111 | * Handled Edge Cases: Empty list, null/undefined expression, expression throwing errors |
| 38 | 112 | */ |
| 39 | 113 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 114 | // Edge Case: Handle null or undefined expression |
| 115 | if (typeof expression !== 'function') { |
| 116 | return new List([]); |
| 117 | } |
| 118 | |
| 119 | // Edge Case: Handle empty list |
| 120 | if (this.length() === 0) { |
| 121 | return new List([]); |
| 122 | } |
| 123 | |
| 124 | const result = []; |
| 125 | for (let i = 0; i < this.values.length; i++) { |
| 126 | try { |
| 127 | // Edge Case: Handle expression function throwing errors |
| 128 | result.push(expression(this.values[i])); |
| 129 | } catch (e) { |
| 130 | // Add undefined for elements that cause expression to throw |
| 131 | result.push(undefined); |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | return new List(result); |
| 41 | 136 | } |
| 42 | 137 | |
| 43 | 138 | /** |
| 44 | | * @return {number} |
| 139 | * Returns the length of the list |
| 140 | * @return {number} The number of elements in the list |
| 141 | * |
| 142 | * Handled Edge Cases: None (this is a straightforward operation) |
| 45 | 143 | */ |
| 46 | 144 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 145 | return this.values.length; |
| 48 | 146 | } |
| 49 | 147 | |
| 50 | 148 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 149 | * Folds the list from the left using a callback function |
| 150 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element |
| 151 | * @param {any} initial - Initial accumulator value |
| 152 | * @return {any} The final accumulator value |
| 153 | * |
| 154 | * Handled Edge Cases: Empty list, null/undefined callback |
| 54 | 155 | */ |
| 55 | 156 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 157 | // Edge Case: Handle null or undefined callback |
| 158 | if (typeof callback !== 'function') { |
| 159 | return initial; |
| 160 | } |
| 161 | |
| 162 | let accumulator = initial; |
| 163 | |
| 164 | // Edge Case: Handle empty list |
| 165 | if (this.length() === 0) { |
| 166 | return accumulator; |
| 167 | } |
| 168 | |
| 169 | for (let i = 0; i < this.values.length; i++) { |
| 170 | try { |
| 171 | // Edge Case: Handle callback function throwing errors |
| 172 | accumulator = callback(accumulator, this.values[i]); |
| 173 | } catch (e) { |
| 174 | // Continue with the current accumulator if callback throws |
| 175 | continue; |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | return accumulator; |
| 57 | 180 | } |
| 58 | 181 | |
| 59 | 182 | /** |
| 60 | | * @param {(acc: any, el: any) => any} callback |
| 61 | | * @param {any} initial |
| 62 | | * @return {any} |
| 183 | * Folds the list from the right using a callback function |
| 184 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element |
| 185 | * @param {any} initial - Initial accumulator value |
| 186 | * @return {any} The final accumulator value |
| 187 | * |
| 188 | * Handled Edge Cases: Empty list, null/undefined callback |
| 63 | 189 | */ |
| 64 | 190 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 191 | // Edge Case: Handle null or undefined callback |
| 192 | if (typeof callback !== 'function') { |
| 193 | return initial; |
| 194 | } |
| 195 | |
| 196 | let accumulator = initial; |
| 197 | |
| 198 | // Edge Case: Handle empty list |
| 199 | if (this.length() === 0) { |
| 200 | return accumulator; |
| 201 | } |
| 202 | |
| 203 | // Process from right to left |
| 204 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 205 | try { |
| 206 | // Edge Case: Handle callback function throwing errors |
| 207 | accumulator = callback(accumulator, this.values[i]); |
| 208 | } catch (e) { |
| 209 | // Continue with the current accumulator if callback throws |
| 210 | continue; |
| 211 | } |
| 212 | } |
| 213 | |
| 214 | return accumulator; |
| 66 | 215 | } |
| 67 | 216 | |
| 68 | 217 | /** |
| 69 | | * @return {List} |
| 218 | * Reverses the list |
| 219 | * @return {List} A new list with elements in reverse order |
| 220 | * |
| 221 | * Handled Edge Cases: Empty list |
| 70 | 222 | */ |
| 71 | 223 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 224 | // Edge Case: Handle empty list |
| 225 | if (this.length() === 0) { |
| 226 | return new List([]); |
| 227 | } |
| 228 | |
| 229 | const result = []; |
| 230 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 231 | result.push(this.values[i]); |
| 232 | } |
| 233 | |
| 234 | return new List(result); |
| 73 | 235 | } |
| 74 | 236 | } |