| 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 list |
| 24 | if (!other) { |
| 25 | return new List(this.values); |
| 26 | } |
| 27 | |
| 28 | // Edge Case: Handle empty lists |
| 29 | if (this.values.length === 0 && other.values.length === 0) { |
| 30 | return new List([]); |
| 31 | } |
| 32 | |
| 33 | if (this.values.length === 0) { |
| 34 | return new List(other.values); |
| 35 | } |
| 36 | |
| 37 | if (other.values.length === 0) { |
| 38 | return new List(this.values); |
| 39 | } |
| 40 | |
| 41 | return new List([...this.values, ...other.values]); |
| 17 | 42 | } |
| 18 | 43 | |
| 19 | 44 | /** |
| 20 | | * @param {List} others |
| 21 | | * @return {List} |
| 45 | * Concatenates multiple lists into one |
| 46 | * @param {List} others - A list of lists to concatenate |
| 47 | * @return {List} A new list with all elements from all lists flattened |
| 48 | * |
| 49 | * Handled Edge Cases: Empty lists, null/undefined others, empty nested lists |
| 22 | 50 | */ |
| 23 | 51 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 52 | // Edge Case: Handle null or undefined others |
| 53 | if (!others) { |
| 54 | return new List(this.values); |
| 55 | } |
| 56 | |
| 57 | let result = [...this.values]; |
| 58 | |
| 59 | // Edge Case: Handle empty others list |
| 60 | if (others.values.length === 0) { |
| 61 | return new List(result); |
| 62 | } |
| 63 | |
| 64 | for (const list of others.values) { |
| 65 | // Edge Case: Handle null or undefined nested lists |
| 66 | if (list && list.values) { |
| 67 | result = [...result, ...list.values]; |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | return new List(result); |
| 25 | 72 | } |
| 26 | 73 | |
| 27 | 74 | /** |
| 28 | | * @param {(any) => boolean} predicate |
| 29 | | * @return {List} |
| 75 | * Filters the list based on a predicate function |
| 76 | * @param {(any) => boolean} predicate - Function to test each element |
| 77 | * @return {List} A new list containing only elements that pass the predicate |
| 78 | * |
| 79 | * Handled Edge Cases: Empty list, null/undefined predicate, predicate throwing errors |
| 30 | 80 | */ |
| 31 | 81 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 82 | // Edge Case: Handle null or undefined predicate |
| 83 | if (typeof predicate !== 'function') { |
| 84 | return new List([]); |
| 85 | } |
| 86 | |
| 87 | // Edge Case: Handle empty list |
| 88 | if (this.values.length === 0) { |
| 89 | return new List([]); |
| 90 | } |
| 91 | |
| 92 | const result = []; |
| 93 | |
| 94 | for (const item of this.values) { |
| 95 | try { |
| 96 | if (predicate(item)) { |
| 97 | result.push(item); |
| 98 | } |
| 99 | } catch (error) { |
| 100 | // Edge Case: Handle predicate function throwing errors |
| 101 | // Silently skip items that cause the predicate to throw |
| 102 | continue; |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | return new List(result); |
| 33 | 107 | } |
| 34 | 108 | |
| 35 | 109 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 110 | * Maps each element in the list using the provided function |
| 111 | * @param {(any) => any} expression - Function to transform each element |
| 112 | * @return {List} A new list with transformed elements |
| 113 | * |
| 114 | * Handled Edge Cases: Empty list, null/undefined expression, expression throwing errors |
| 38 | 115 | */ |
| 39 | 116 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 117 | // Edge Case: Handle null or undefined expression |
| 118 | if (typeof expression !== 'function') { |
| 119 | return new List([]); |
| 120 | } |
| 121 | |
| 122 | // Edge Case: Handle empty list |
| 123 | if (this.values.length === 0) { |
| 124 | return new List([]); |
| 125 | } |
| 126 | |
| 127 | const result = []; |
| 128 | |
| 129 | for (const item of this.values) { |
| 130 | try { |
| 131 | result.push(expression(item)); |
| 132 | } catch (error) { |
| 133 | // Edge Case: Handle expression function throwing errors |
| 134 | // Push undefined for items that cause the expression to throw |
| 135 | result.push(undefined); |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | return new List(result); |
| 41 | 140 | } |
| 42 | 141 | |
| 43 | 142 | /** |
| 44 | | * @return {number} |
| 143 | * Returns the length of the list |
| 144 | * @return {number} The number of elements in the list |
| 145 | * |
| 146 | * Handled Edge Cases: None (this operation is always safe) |
| 45 | 147 | */ |
| 46 | 148 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 149 | return this.values.length; |
| 48 | 150 | } |
| 49 | 151 | |
| 50 | 152 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 153 | * Folds the list from the left using a callback function and initial accumulator |
| 154 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element |
| 155 | * @param {any} initial - Initial accumulator value |
| 156 | * @return {any} The final accumulator value |
| 157 | * |
| 158 | * Handled Edge Cases: Empty list, null/undefined callback |
| 54 | 159 | */ |
| 55 | 160 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 161 | // Edge Case: Handle null or undefined callback |
| 162 | if (typeof callback !== 'function') { |
| 163 | return initial; |
| 164 | } |
| 165 | |
| 166 | // Edge Case: Handle empty list |
| 167 | if (this.values.length === 0) { |
| 168 | return initial; |
| 169 | } |
| 170 | |
| 171 | let accumulator = initial; |
| 172 | |
| 173 | for (const item of this.values) { |
| 174 | accumulator = callback(accumulator, item); |
| 175 | } |
| 176 | |
| 177 | return accumulator; |
| 57 | 178 | } |
| 58 | 179 | |
| 59 | 180 | /** |
| 60 | | * @param {(acc: any, el: any) => any} callback |
| 61 | | * @param {any} initial |
| 62 | | * @return {any} |
| 181 | * Folds the list from the right using a callback function and initial accumulator |
| 182 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element |
| 183 | * @param {any} initial - Initial accumulator value |
| 184 | * @return {any} The final accumulator value |
| 185 | * |
| 186 | * Handled Edge Cases: Empty list, null/undefined callback |
| 63 | 187 | */ |
| 64 | 188 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 189 | // Edge Case: Handle null or undefined callback |
| 190 | if (typeof callback !== 'function') { |
| 191 | return initial; |
| 192 | } |
| 193 | |
| 194 | // Edge Case: Handle empty list |
| 195 | if (this.values.length === 0) { |
| 196 | return initial; |
| 197 | } |
| 198 | |
| 199 | let accumulator = initial; |
| 200 | |
| 201 | // Process from right to left |
| 202 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 203 | accumulator = callback(accumulator, this.values[i]); |
| 204 | } |
| 205 | |
| 206 | return accumulator; |
| 66 | 207 | } |
| 67 | 208 | |
| 68 | 209 | /** |
| 69 | | * @return {List} |
| 210 | * Reverses the list |
| 211 | * @return {List} A new list with elements in reverse order |
| 212 | * |
| 213 | * Handled Edge Cases: Empty list |
| 70 | 214 | */ |
| 71 | 215 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 216 | // Edge Case: Handle empty list |
| 217 | if (this.values.length === 0) { |
| 218 | return new List([]); |
| 219 | } |
| 220 | |
| 221 | const result = []; |
| 222 | |
| 223 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 224 | result.push(this.values[i]); |
| 225 | } |
| 226 | |
| 227 | return new List(result); |
| 73 | 228 | } |
| 74 | 229 | } |