| 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, nested empty lists |
| 22 | 50 | */ |
| 23 | 51 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 52 | let result = [...this.values]; |
| 53 | |
| 54 | // Edge Case: Handle empty others list |
| 55 | if (!others || others.length() === 0) { |
| 56 | return new List(result); |
| 57 | } |
| 58 | |
| 59 | // Process each list in others |
| 60 | for (let i = 0; i < others.values.length; i++) { |
| 61 | const list = others.values[i]; |
| 62 | if (list instanceof List) { |
| 63 | result = [...result, ...list.values]; |
| 64 | } else { |
| 65 | result.push(list); |
| 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, all elements filtered out, no elements filtered out |
| 30 | 78 | */ |
| 31 | 79 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 80 | // Edge Case: Handle empty list |
| 81 | if (this.values.length === 0) { |
| 82 | return new List([]); |
| 83 | } |
| 84 | |
| 85 | const result = []; |
| 86 | for (let i = 0; i < this.values.length; i++) { |
| 87 | if (predicate(this.values[i])) { |
| 88 | result.push(this.values[i]); |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | return new List(result); |
| 33 | 93 | } |
| 34 | 94 | |
| 35 | 95 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 96 | * Transforms each element using the provided function |
| 97 | * @param {(any) => any} expression - Function to transform each element |
| 98 | * @return {List} A new list with transformed elements |
| 99 | * |
| 100 | * Handled Edge Cases: Empty list |
| 38 | 101 | */ |
| 39 | 102 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 103 | // Edge Case: Handle empty list |
| 104 | if (this.values.length === 0) { |
| 105 | return new List([]); |
| 106 | } |
| 107 | |
| 108 | const result = []; |
| 109 | for (let i = 0; i < this.values.length; i++) { |
| 110 | result.push(expression(this.values[i])); |
| 111 | } |
| 112 | |
| 113 | return new List(result); |
| 41 | 114 | } |
| 42 | 115 | |
| 43 | 116 | /** |
| 44 | | * @return {number} |
| 117 | * Returns the number of elements in the list |
| 118 | * @return {number} The length of the list |
| 119 | * |
| 120 | * Handled Edge Cases: Empty list |
| 45 | 121 | */ |
| 46 | 122 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 123 | // Edge Case: Handle empty list |
| 124 | let count = 0; |
| 125 | for (let i = 0; i < this.values.length; i++) { |
| 126 | count++; |
| 127 | } |
| 128 | return count; |
| 48 | 129 | } |
| 49 | 130 | |
| 50 | 131 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 132 | * Folds the list from the left using a callback function |
| 133 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element |
| 134 | * @param {any} initial - Initial accumulator value |
| 135 | * @return {any} The final accumulator value |
| 136 | * |
| 137 | * Handled Edge Cases: Empty list |
| 54 | 138 | */ |
| 55 | 139 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 140 | // Edge Case: Handle empty list |
| 141 | if (this.values.length === 0) { |
| 142 | return initial; |
| 143 | } |
| 144 | |
| 145 | let accumulator = initial; |
| 146 | for (let i = 0; i < this.values.length; i++) { |
| 147 | accumulator = callback(accumulator, this.values[i]); |
| 148 | } |
| 149 | |
| 150 | return accumulator; |
| 57 | 151 | } |
| 58 | 152 | |
| 59 | 153 | /** |
| 60 | | * @param {(acc: any, el: any) => any} callback |
| 61 | | * @param {any} initial |
| 62 | | * @return {any} |
| 154 | * Folds the list from the right using a callback function |
| 155 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element |
| 156 | * @param {any} initial - Initial accumulator value |
| 157 | * @return {any} The final accumulator value |
| 158 | * |
| 159 | * Handled Edge Cases: Empty list |
| 63 | 160 | */ |
| 64 | 161 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 162 | // Edge Case: Handle empty list |
| 163 | if (this.values.length === 0) { |
| 164 | return initial; |
| 165 | } |
| 166 | |
| 167 | let accumulator = initial; |
| 168 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 169 | accumulator = callback(accumulator, this.values[i]); |
| 170 | } |
| 171 | |
| 172 | return accumulator; |
| 66 | 173 | } |
| 67 | 174 | |
| 68 | 175 | /** |
| 69 | | * @return {List} |
| 176 | * Reverses the order of elements in the list |
| 177 | * @return {List} A new list with elements in reverse order |
| 178 | * |
| 179 | * Handled Edge Cases: Empty list, single element list |
| 70 | 180 | */ |
| 71 | 181 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 182 | // Edge Case: Handle empty list |
| 183 | if (this.values.length === 0) { |
| 184 | return new List([]); |
| 185 | } |
| 186 | |
| 187 | // Edge Case: Handle single element list |
| 188 | if (this.values.length === 1) { |
| 189 | return new List([this.values[0]]); |
| 190 | } |
| 191 | |
| 192 | const result = []; |
| 193 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 194 | result.push(this.values[i]); |
| 195 | } |
| 196 | |
| 197 | return new List(result); |
| 73 | 198 | } |
| 74 | 199 | } |