| 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 for both this and other lists |
| 14 | 20 | */ |
| 15 | 21 | append(other) { |
| 16 | | throw new Error('Remove this line and implement the function'); |
| 22 | // Edge Case: When both lists are empty |
| 23 | if (this.values.length === 0 && other.values.length === 0) { |
| 24 | return new List([]); |
| 25 | } |
| 26 | |
| 27 | // Edge Case: When this list is empty |
| 28 | if (this.values.length === 0) { |
| 29 | return new List([...other.values]); |
| 30 | } |
| 31 | |
| 32 | // Edge Case: When other list is empty |
| 33 | if (other.values.length === 0) { |
| 34 | return new List([...this.values]); |
| 35 | } |
| 36 | |
| 37 | const result = []; |
| 38 | for (let i = 0; i < this.values.length; i++) { |
| 39 | result.push(this.values[i]); |
| 40 | } |
| 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 a list of lists into one flattened list. |
| 50 | * @param {List} others - A list containing other lists to concatenate. |
| 51 | * @return {List} A new list with all items from all lists. |
| 52 | * Handled Edge Cases: Empty list of lists, lists with empty sublists |
| 22 | 53 | */ |
| 23 | 54 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 55 | // Edge Case: When others is empty |
| 56 | if (others.values.length === 0) { |
| 57 | return new List([...this.values]); |
| 58 | } |
| 59 | |
| 60 | const result = []; |
| 61 | |
| 62 | // Add items from this list |
| 63 | for (let i = 0; i < this.values.length; i++) { |
| 64 | result.push(this.values[i]); |
| 65 | } |
| 66 | |
| 67 | // Add items from each list in others |
| 68 | for (let i = 0; i < others.values.length; i++) { |
| 69 | const sublist = others.values[i]; |
| 70 | // Edge Case: When sublist is not a List instance (defensive programming) |
| 71 | if (sublist instanceof List) { |
| 72 | for (let j = 0; j < sublist.values.length; j++) { |
| 73 | result.push(sublist.values[j]); |
| 74 | } |
| 75 | } else { |
| 76 | // If it's a regular array, add its elements |
| 77 | for (let j = 0; j < sublist.length; j++) { |
| 78 | result.push(sublist[j]); |
| 79 | } |
| 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 {(any) => boolean} predicate - Function to test each item. |
| 89 | * @return {List} A new list containing only items that satisfy the predicate. |
| 90 | * Handled Edge Cases: Empty list, no items match predicate, all items match predicate |
| 30 | 91 | */ |
| 31 | 92 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 93 | // Edge Case: When this list is empty |
| 94 | if (this.values.length === 0) { |
| 95 | return new List([]); |
| 96 | } |
| 97 | |
| 98 | const result = []; |
| 99 | for (let i = 0; i < this.values.length; i++) { |
| 100 | if (predicate(this.values[i])) { |
| 101 | result.push(this.values[i]); |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | return new List(result); |
| 33 | 106 | } |
| 34 | 107 | |
| 35 | 108 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 109 | * Transforms each item in the list using a mapping function. |
| 110 | * @param {(any) => any} expression - Function to transform each item. |
| 111 | * @return {List} A new list with transformed items. |
| 112 | * Handled Edge Cases: Empty list |
| 38 | 113 | */ |
| 39 | 114 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 115 | // Edge Case: When this list is empty |
| 116 | if (this.values.length === 0) { |
| 117 | return new List([]); |
| 118 | } |
| 119 | |
| 120 | const result = []; |
| 121 | for (let i = 0; i < this.values.length; i++) { |
| 122 | result.push(expression(this.values[i])); |
| 123 | } |
| 124 | |
| 125 | return new List(result); |
| 41 | 126 | } |
| 42 | 127 | |
| 43 | 128 | /** |
| 44 | | * @return {number} |
| 129 | * Returns the number of items in the list. |
| 130 | * @return {number} The length of the list. |
| 131 | * Handled Edge Cases: Empty list |
| 45 | 132 | */ |
| 46 | 133 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 134 | // Edge Case: When this list is empty |
| 135 | let count = 0; |
| 136 | for (let i = 0; i < this.values.length; i++) { |
| 137 | count++; |
| 138 | } |
| 139 | return count; |
| 48 | 140 | } |
| 49 | 141 | |
| 50 | 142 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 143 | * Folds (reduces) the list from left to right using a callback function. |
| 144 | * @param {(acc: any, el: any) => any} callback - Function to apply to each item. |
| 145 | * @param {any} initial - Initial accumulator value. |
| 146 | * @return {any} The final accumulator value. |
| 147 | * Handled Edge Cases: Empty list |
| 54 | 148 | */ |
| 55 | 149 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 150 | // Edge Case: When this list is empty |
| 151 | if (this.values.length === 0) { |
| 152 | return initial; |
| 153 | } |
| 154 | |
| 155 | let accumulator = initial; |
| 156 | for (let i = 0; i < this.values.length; i++) { |
| 157 | accumulator = callback(accumulator, this.values[i]); |
| 158 | } |
| 159 | |
| 160 | return accumulator; |
| 57 | 161 | } |
| 58 | 162 | |
| 59 | 163 | /** |
| 60 | | * @param {(acc: any, el: any) => any} callback |
| 61 | | * @param {any} initial |
| 62 | | * @return {any} |
| 164 | * Folds (reduces) the list from right to left using a callback function. |
| 165 | * @param {(acc: any, el: any) => any} callback - Function to apply to each item. |
| 166 | * @param {any} initial - Initial accumulator value. |
| 167 | * @return {any} The final accumulator value. |
| 168 | * Handled Edge Cases: Empty list |
| 63 | 169 | */ |
| 64 | 170 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 171 | // Edge Case: When this list is empty |
| 172 | if (this.values.length === 0) { |
| 173 | return initial; |
| 174 | } |
| 175 | |
| 176 | let accumulator = initial; |
| 177 | // Process from right to left |
| 178 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 179 | accumulator = callback(accumulator, this.values[i]); |
| 180 | } |
| 181 | |
| 182 | return accumulator; |
| 66 | 183 | } |
| 67 | 184 | |
| 68 | 185 | /** |
| 69 | | * @return {List} |
| 186 | * Returns a new list with items in reverse order. |
| 187 | * @return {List} A new list with reversed items. |
| 188 | * Handled Edge Cases: Empty list |
| 70 | 189 | */ |
| 71 | 190 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 191 | // Edge Case: When this list is empty |
| 192 | if (this.values.length === 0) { |
| 193 | return new List([]); |
| 194 | } |
| 195 | |
| 196 | const result = []; |
| 197 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 198 | result.push(this.values[i]); |
| 199 | } |
| 200 | |
| 201 | return new List(result); |
| 73 | 202 | } |
| 74 | 203 | } |