| 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 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 |
| 14 | 19 | */ |
| 15 | 20 | append(other) { |
| 16 | | throw new Error('Remove this line and implement the function'); |
| 21 | // Edge Case: Appending an empty list should return a copy of the original list |
| 22 | if (!other || !other.values || other.length() === 0) { |
| 23 | return new List(this.values); |
| 24 | } |
| 25 | |
| 26 | const result = []; |
| 27 | for (let i = 0; i < this.values.length; i++) { |
| 28 | result.push(this.values[i]); |
| 29 | } |
| 30 | for (let i = 0; i < other.values.length; i++) { |
| 31 | result.push(other.values[i]); |
| 32 | } |
| 33 | return new List(result); |
| 34 | // Handled Edge Cases: Appending empty list |
| 17 | 35 | } |
| 18 | 36 | |
| 19 | 37 | /** |
| 20 | | * @param {List} others |
| 21 | | * @return {List} |
| 38 | * Concatenates this list with a list of lists |
| 39 | * @param {List} others - A list containing other lists to concatenate |
| 40 | * @return {List} A new flattened list containing all items |
| 22 | 41 | */ |
| 23 | 42 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 43 | // Edge Case: Concatenating with an empty list of lists |
| 44 | if (!others || !others.values || others.length() === 0) { |
| 45 | return new List(this.values); |
| 46 | } |
| 47 | |
| 48 | let result = []; |
| 49 | |
| 50 | // Add items from the current list |
| 51 | for (let i = 0; i < this.values.length; i++) { |
| 52 | result.push(this.values[i]); |
| 53 | } |
| 54 | |
| 55 | // Add items from each list in others |
| 56 | for (let i = 0; i < others.values.length; i++) { |
| 57 | const list = others.values[i]; |
| 58 | // Edge Case: Handling null or undefined elements in the list of lists |
| 59 | if (list && list.values) { |
| 60 | for (let j = 0; j < list.values.length; j++) { |
| 61 | result.push(list.values[j]); |
| 62 | } |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | return new List(result); |
| 67 | // Handled Edge Cases: Concatenating with empty list, null/undefined elements in lists |
| 25 | 68 | } |
| 26 | 69 | |
| 27 | 70 | /** |
| 28 | | * @param {(any) => boolean} predicate |
| 29 | | * @return {List} |
| 71 | * Filters the list based on a predicate function |
| 72 | * @param {(any) => boolean} predicate - Function to test each element |
| 73 | * @return {List} A new list containing only elements that satisfy the predicate |
| 30 | 74 | */ |
| 31 | 75 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 76 | // Edge Case: Empty list should return an empty list |
| 77 | if (this.values.length === 0) { |
| 78 | return new List([]); |
| 79 | } |
| 80 | |
| 81 | // Edge Case: Invalid predicate function |
| 82 | if (typeof predicate !== 'function') { |
| 83 | throw new Error('Predicate must be a function'); |
| 84 | } |
| 85 | |
| 86 | const result = []; |
| 87 | for (let i = 0; i < this.values.length; i++) { |
| 88 | if (predicate(this.values[i])) { |
| 89 | result.push(this.values[i]); |
| 90 | } |
| 91 | } |
| 92 | return new List(result); |
| 93 | // Handled Edge Cases: Empty list, invalid predicate function |
| 33 | 94 | } |
| 34 | 95 | |
| 35 | 96 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 97 | * Maps each element in the list using the provided expression function |
| 98 | * @param {(any) => any} expression - Function to transform each element |
| 99 | * @return {List} A new list with transformed elements |
| 38 | 100 | */ |
| 39 | 101 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 102 | // Edge Case: Empty list should return an empty list |
| 103 | if (this.values.length === 0) { |
| 104 | return new List([]); |
| 105 | } |
| 106 | |
| 107 | // Edge Case: Invalid expression function |
| 108 | if (typeof expression !== 'function') { |
| 109 | throw new Error('Expression must be a function'); |
| 110 | } |
| 111 | |
| 112 | const result = []; |
| 113 | for (let i = 0; i < this.values.length; i++) { |
| 114 | result.push(expression(this.values[i])); |
| 115 | } |
| 116 | return new List(result); |
| 117 | // Handled Edge Cases: Empty list, invalid expression function |
| 41 | 118 | } |
| 42 | 119 | |
| 43 | 120 | /** |
| 44 | | * @return {number} |
| 121 | * Returns the number of elements in the list |
| 122 | * @return {number} The length of the list |
| 45 | 123 | */ |
| 46 | 124 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 125 | // Edge Case: Count elements properly even when list has no elements |
| 126 | let count = 0; |
| 127 | for (let i = 0; i < this.values.length; i++) { |
| 128 | count++; |
| 129 | } |
| 130 | return count; |
| 131 | // Handled Edge Cases: Empty list |
| 48 | 132 | } |
| 49 | 133 | |
| 50 | 134 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 135 | * Folds the list from the left using a callback function and initial accumulator |
| 136 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element |
| 137 | * @param {any} initial - Initial accumulator value |
| 138 | * @return {any} The final accumulator value |
| 54 | 139 | */ |
| 55 | 140 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 141 | // Edge Case: Invalid callback function |
| 142 | if (typeof callback !== 'function') { |
| 143 | throw new Error('Callback must be a function'); |
| 144 | } |
| 145 | |
| 146 | // Edge Case: Empty list should return the initial value |
| 147 | if (this.values.length === 0) { |
| 148 | return initial; |
| 149 | } |
| 150 | |
| 151 | let accumulator = initial; |
| 152 | for (let i = 0; i < this.values.length; i++) { |
| 153 | accumulator = callback(accumulator, this.values[i]); |
| 154 | } |
| 155 | return accumulator; |
| 156 | // Handled Edge Cases: Empty list, invalid callback function |
| 57 | 157 | } |
| 58 | 158 | |
| 59 | 159 | /** |
| 60 | | * @param {(acc: any, el: any) => any} callback |
| 61 | | * @param {any} initial |
| 62 | | * @return {any} |
| 160 | * Folds the list from the right using a callback function and initial accumulator |
| 161 | * @param {(acc: any, el: any) => any} callback - Function to apply to each element |
| 162 | * @param {any} initial - Initial accumulator value |
| 163 | * @return {any} The final accumulator value |
| 63 | 164 | */ |
| 64 | 165 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 166 | // Edge Case: Invalid callback function |
| 167 | if (typeof callback !== 'function') { |
| 168 | throw new Error('Callback must be a function'); |
| 169 | } |
| 170 | |
| 171 | // Edge Case: Empty list should return the initial value |
| 172 | if (this.values.length === 0) { |
| 173 | return initial; |
| 174 | } |
| 175 | |
| 176 | let accumulator = initial; |
| 177 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 178 | accumulator = callback(accumulator, this.values[i]); |
| 179 | } |
| 180 | return accumulator; |
| 181 | // Handled Edge Cases: Empty list, invalid callback function |
| 66 | 182 | } |
| 67 | 183 | |
| 68 | 184 | /** |
| 69 | | * @return {List} |
| 185 | * Returns a new list with elements in reverse order |
| 186 | * @return {List} A new list with reversed elements |
| 70 | 187 | */ |
| 71 | 188 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 189 | // Edge Case: Reversing an empty list should return an empty list |
| 190 | if (this.values.length === 0) { |
| 191 | return new List([]); |
| 192 | } |
| 193 | |
| 194 | const result = []; |
| 195 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 196 | result.push(this.values[i]); |
| 197 | } |
| 198 | return new List(result); |
| 199 | // Handled Edge Cases: Empty list |
| 73 | 200 | } |
| 74 | 201 | } |