| 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 | // Store values without using spread operator or other built-in functions |
| 13 | this.values = []; |
| 14 | for (let i = 0; i < values.length; i++) { |
| 15 | this.values[i] = values[i]; |
| 16 | } |
| 9 | 17 | } |
| 10 | 18 | |
| 11 | 19 | /** |
| 12 | | * @param {List} other |
| 13 | | * @return {List} |
| 20 | * Appends all items from another list to the end of this list. |
| 21 | * @param {List} other - The list to append. |
| 22 | * @return {List} A new List containing all items from both lists. |
| 23 | * |
| 24 | * Handled Edge Cases: |
| 25 | * - Appending an empty list to another list |
| 26 | * - Appending a list to an empty list |
| 14 | 27 | */ |
| 15 | 28 | append(other) { |
| 16 | | throw new Error('Remove this line and implement the function'); |
| 29 | // Create a new array to hold all values without using spread operator |
| 30 | const result = []; |
| 31 | |
| 32 | // Copy values from this list |
| 33 | for (let i = 0; i < this.values.length; i++) { |
| 34 | result[i] = this.values[i]; |
| 35 | } |
| 36 | |
| 37 | // Copy values from other list |
| 38 | for (let i = 0; i < other.values.length; i++) { |
| 39 | result[this.values.length + i] = other.values[i]; |
| 40 | } |
| 41 | |
| 42 | return new List(result); |
| 17 | 43 | } |
| 18 | 44 | |
| 19 | 45 | /** |
| 20 | | * @param {List} others |
| 21 | | * @return {List} |
| 46 | * Concatenates a series of lists into one flattened list. |
| 47 | * @param {List} others - A list containing other lists to concatenate. |
| 48 | * @return {List} A new List with all items from all lists. |
| 49 | * |
| 50 | * Handled Edge Cases: |
| 51 | * - Concatenating with an empty list of lists |
| 52 | * - Concatenating when the input list contains empty lists |
| 22 | 53 | */ |
| 23 | 54 | concat(others) { |
| 24 | | throw new Error('Remove this line and implement the function'); |
| 55 | // Start with values from this list |
| 56 | const result = []; |
| 57 | for (let i = 0; i < this.values.length; i++) { |
| 58 | result[i] = this.values[i]; |
| 59 | } |
| 60 | |
| 61 | // Add values from each list in others |
| 62 | let resultIndex = this.values.length; |
| 63 | for (let i = 0; i < others.values.length; i++) { |
| 64 | const list = others.values[i]; |
| 65 | if (list instanceof List) { |
| 66 | for (let j = 0; j < list.values.length; j++) { |
| 67 | result[resultIndex] = list.values[j]; |
| 68 | resultIndex++; |
| 69 | } |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | return new List(result); |
| 25 | 74 | } |
| 26 | 75 | |
| 27 | 76 | /** |
| 28 | | * @param {(any) => boolean} predicate |
| 29 | | * @return {List} |
| 77 | * Filters the list based on a predicate function. |
| 78 | * @param {(any) => boolean} predicate - Function to test each item. |
| 79 | * @return {List} A new List containing only items that satisfy the predicate. |
| 80 | * |
| 81 | * Handled Edge Cases: |
| 82 | * - Filtering an empty list |
| 83 | * - Predicate that matches no items |
| 84 | * - Predicate that matches all items |
| 30 | 85 | */ |
| 31 | 86 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 87 | const result = []; |
| 88 | let resultIndex = 0; |
| 89 | |
| 90 | for (let i = 0; i < this.values.length; i++) { |
| 91 | if (predicate(this.values[i])) { |
| 92 | result[resultIndex] = this.values[i]; |
| 93 | resultIndex++; |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | return new List(result); |
| 33 | 98 | } |
| 34 | 99 | |
| 35 | 100 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 101 | * Maps each item in the list using a provided function. |
| 102 | * @param {(any) => any} expression - Function to apply to each item. |
| 103 | * @return {List} A new List with the results of applying the function. |
| 104 | * |
| 105 | * Handled Edge Cases: |
| 106 | * - Mapping an empty list |
| 38 | 107 | */ |
| 39 | 108 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 109 | const result = []; |
| 110 | |
| 111 | for (let i = 0; i < this.values.length; i++) { |
| 112 | result[i] = expression(this.values[i]); |
| 113 | } |
| 114 | |
| 115 | return new List(result); |
| 41 | 116 | } |
| 42 | 117 | |
| 43 | 118 | /** |
| 44 | | * @return {number} |
| 119 | * Returns the number of items in the list. |
| 120 | * @return {number} The length of the list. |
| 121 | * |
| 122 | * Handled Edge Cases: |
| 123 | * - Getting length of an empty list |
| 45 | 124 | */ |
| 46 | 125 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 126 | // Count elements manually without using array.length property directly in logic |
| 127 | let count = 0; |
| 128 | for (let i = 0; i < this.values.length; i++) { |
| 129 | count++; |
| 130 | } |
| 131 | |
| 132 | return count; |
| 48 | 133 | } |
| 49 | 134 | |
| 50 | 135 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 136 | * Folds (reduces) the list from the left using a callback function. |
| 137 | * @param {(acc: any, el: any) => any} callback - Function to apply to each item. |
| 138 | * @param {any} initial - Initial accumulator value. |
| 139 | * @return {any} The final accumulator value. |
| 140 | * |
| 141 | * Handled Edge Cases: |
| 142 | * - Folding an empty list (returns initial value) |
| 54 | 143 | */ |
| 55 | 144 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 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 (reduces) the list from the right using a callback function. |
| 155 | * @param {(acc: any, el: any) => any} callback - Function to apply to each item. |
| 156 | * @param {any} initial - Initial accumulator value. |
| 157 | * @return {any} The final accumulator value. |
| 158 | * |
| 159 | * Handled Edge Cases: |
| 160 | * - Folding an empty list (returns initial value) |
| 63 | 161 | */ |
| 64 | 162 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 163 | let accumulator = initial; |
| 164 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 165 | accumulator = callback(accumulator, this.values[i]); |
| 166 | } |
| 167 | |
| 168 | return accumulator; |
| 66 | 169 | } |
| 67 | 170 | |
| 68 | 171 | /** |
| 69 | | * @return {List} |
| 172 | * Reverses the order of items in the list. |
| 173 | * @return {List} A new List with items in reversed order. |
| 174 | * |
| 175 | * Handled Edge Cases: |
| 176 | * - Reversing an empty list |
| 70 | 177 | */ |
| 71 | 178 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 179 | const result = []; |
| 180 | |
| 181 | for (let i = 0; i < this.values.length; i++) { |
| 182 | result[i] = this.values[this.values.length - 1 - i]; |
| 183 | } |
| 184 | |
| 185 | return new List(result); |
| 73 | 186 | } |
| 74 | 187 | } |