| 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 another list to this list. |
| 17 | * @param {List} other - The list to append. |
| 18 | * @return {List} A new list containing elements from both lists. |
| 19 | * |
| 20 | * Handled Edge Cases: |
| 21 | * - Appending an empty list to a non-empty list |
| 22 | * - Appending a non-empty list to an empty list |
| 23 | * - Appending two empty lists |
| 14 | 24 | */ |
| 15 | 25 | append(other) { |
| 16 | | throw new Error('Remove this line and implement the function'); |
| 26 | // Edge Case: Appending an empty list to a non-empty list |
| 27 | if (other.length() === 0) { |
| 28 | return new List(this.values); |
| 29 | } |
| 30 | |
| 31 | // Edge Case: Appending a non-empty list to an empty list |
| 32 | if (this.length() === 0) { |
| 33 | return new List(other.values); |
| 34 | } |
| 35 | |
| 36 | // Edge Case: Appending two empty lists |
| 37 | if (this.length() === 0 && other.length() === 0) { |
| 38 | return new List(); |
| 39 | } |
| 40 | |
| 41 | const result = []; |
| 42 | for (let i = 0; i < this.values.length; i++) { |
| 43 | result.push(this.values[i]); |
| 44 | } |
| 45 | for (let i = 0; i < other.values.length; i++) { |
| 46 | result.push(other.values[i]); |
| 47 | } |
| 48 | return new List(result); |
| 17 | 49 | } |
| 18 | 50 | |
| 19 | 51 | /** |
| 20 | | * @param {List} others |
| 21 | | * @return {List} |
| 52 | * Concatenates multiple lists into one. |
| 53 | * @param {List} others - A list of lists to concatenate. |
| 54 | * @return {List} A new list with all elements from all lists. |
| 55 | * |
| 56 | * Handled Edge Cases: |
| 57 | * - Concatenating with an empty list of lists |
| 58 | * - Concatenating empty lists |
| 59 | * - Concatenating lists with mixed empty and non-empty lists |
| 22 | 60 | */ |
| 23 | 61 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 62 | // Edge Case: Concatenating with an empty list of lists |
| 63 | if (others.length() === 0) { |
| 64 | return new List(this.values); |
| 65 | } |
| 66 | |
| 67 | let result = []; |
| 68 | |
| 69 | // Add elements from the current list |
| 70 | for (let i = 0; i < this.values.length; i++) { |
| 71 | result.push(this.values[i]); |
| 72 | } |
| 73 | |
| 74 | // Add elements from each list in others |
| 75 | for (let i = 0; i < others.values.length; i++) { |
| 76 | const list = others.values[i]; |
| 77 | |
| 78 | // Edge Case: Handling empty lists in the concatenation |
| 79 | if (list instanceof List) { |
| 80 | for (let j = 0; j < list.values.length; j++) { |
| 81 | result.push(list.values[j]); |
| 82 | } |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | return new List(result); |
| 25 | 87 | } |
| 26 | 88 | |
| 27 | 89 | /** |
| 28 | | * @param {(any) => boolean} predicate |
| 29 | | * @return {List} |
| 90 | * Filters the list based on a predicate function. |
| 91 | * @param {(any) => boolean} predicate - Function to test each element. |
| 92 | * @return {List} A new list with elements that pass the predicate test. |
| 93 | * |
| 94 | * Handled Edge Cases: |
| 95 | * - Filtering an empty list |
| 96 | * - Predicate that matches no elements |
| 97 | * - Predicate that matches all elements |
| 30 | 98 | */ |
| 31 | 99 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 100 | // Edge Case: Filtering an empty list |
| 101 | if (this.length() === 0) { |
| 102 | return new List(); |
| 103 | } |
| 104 | |
| 105 | const result = []; |
| 106 | for (let i = 0; i < this.values.length; i++) { |
| 107 | // Edge Case: Predicate that matches no elements |
| 108 | // Edge Case: Predicate that matches all elements |
| 109 | if (predicate(this.values[i])) { |
| 110 | result.push(this.values[i]); |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | return new List(result); |
| 33 | 115 | } |
| 34 | 116 | |
| 35 | 117 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 118 | * Transforms each element using a mapping function. |
| 119 | * @param {(any) => any} expression - Function to transform each element. |
| 120 | * @return {List} A new list with transformed elements. |
| 121 | * |
| 122 | * Handled Edge Cases: |
| 123 | * - Mapping an empty list |
| 124 | * - Mapping with a function that returns undefined |
| 38 | 125 | */ |
| 39 | 126 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 127 | // Edge Case: Mapping an empty list |
| 128 | if (this.length() === 0) { |
| 129 | return new List(); |
| 130 | } |
| 131 | |
| 132 | const result = []; |
| 133 | for (let i = 0; i < this.values.length; i++) { |
| 134 | // Edge Case: Mapping with a function that returns undefined |
| 135 | result.push(expression(this.values[i])); |
| 136 | } |
| 137 | |
| 138 | return new List(result); |
| 41 | 139 | } |
| 42 | 140 | |
| 43 | 141 | /** |
| 44 | | * @return {number} |
| 142 | * Returns the number of elements in the list. |
| 143 | * @return {number} The length of the list. |
| 144 | * |
| 145 | * Handled Edge Cases: |
| 146 | * - Getting length of an empty list |
| 45 | 147 | */ |
| 46 | 148 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 149 | // Edge Case: Getting length of an empty list |
| 150 | let count = 0; |
| 151 | for (let i = 0; i < this.values.length; i++) { |
| 152 | count++; |
| 153 | } |
| 154 | return count; |
| 48 | 155 | } |
| 49 | 156 | |
| 50 | 157 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 158 | * Folds the list from the left using a callback function. |
| 159 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element. |
| 160 | * @param {any} initial - Initial accumulator value. |
| 161 | * @return {any} The final accumulator value. |
| 162 | * |
| 163 | * Handled Edge Cases: |
| 164 | * - Folding an empty list |
| 165 | * - Folding with a callback that returns null or undefined |
| 54 | 166 | */ |
| 55 | 167 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 168 | // Edge Case: Folding an empty list |
| 169 | if (this.length() === 0) { |
| 170 | return initial; |
| 171 | } |
| 172 | |
| 173 | let accumulator = initial; |
| 174 | for (let i = 0; i < this.values.length; i++) { |
| 175 | // Edge Case: Folding with a callback that returns null or undefined |
| 176 | accumulator = callback(accumulator, this.values[i]); |
| 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: |
| 189 | * - Folding an empty list |
| 190 | * - Folding with a callback that returns null or undefined |
| 63 | 191 | */ |
| 64 | 192 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 193 | // Edge Case: Folding an empty list |
| 194 | if (this.length() === 0) { |
| 195 | return initial; |
| 196 | } |
| 197 | |
| 198 | let accumulator = initial; |
| 199 | // Process elements from right to left |
| 200 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 201 | // Edge Case: Folding with a callback that returns null or undefined |
| 202 | accumulator = callback(accumulator, this.values[i]); |
| 203 | } |
| 204 | |
| 205 | return accumulator; |
| 66 | 206 | } |
| 67 | 207 | |
| 68 | 208 | /** |
| 69 | | * @return {List} |
| 209 | * Reverses the order of elements in the list. |
| 210 | * @return {List} A new list with elements in reverse order. |
| 211 | * |
| 212 | * Handled Edge Cases: |
| 213 | * - Reversing an empty list |
| 214 | * - Reversing a list with one element |
| 70 | 215 | */ |
| 71 | 216 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 217 | // Edge Case: Reversing an empty list |
| 218 | if (this.length() === 0) { |
| 219 | return new List(); |
| 220 | } |
| 221 | |
| 222 | // Edge Case: Reversing a list with one element |
| 223 | if (this.length() === 1) { |
| 224 | return new List([this.values[0]]); |
| 225 | } |
| 226 | |
| 227 | const result = []; |
| 228 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 229 | result.push(this.values[i]); |
| 230 | } |
| 231 | |
| 232 | return new List(result); |
| 73 | 233 | } |
| 74 | 234 | } |