| 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 |
| 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.values.length === 0) { |
| 23 | return new List(this.values); |
| 24 | } |
| 25 | |
| 26 | const combined = []; |
| 27 | for (let i = 0; i < this.values.length; i++) { |
| 28 | combined.push(this.values[i]); |
| 29 | } |
| 30 | for (let i = 0; i < other.values.length; i++) { |
| 31 | combined.push(other.values[i]); |
| 32 | } |
| 33 | return new List(combined); |
| 34 | // Handled Edge Cases: Appending empty list |
| 17 | 35 | } |
| 18 | 36 | |
| 19 | 37 | /** |
| 20 | | * @param {List} others |
| 21 | | * @return {List} |
| 38 | * Concatenates multiple lists into one |
| 39 | * @param {List} others - A list of lists to concatenate |
| 40 | * @return {List} A new list with all elements from all lists flattened |
| 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.values.length === 0) { |
| 45 | return new List(this.values); |
| 46 | } |
| 47 | |
| 48 | let result = new List(this.values); |
| 49 | for (let i = 0; i < others.values.length; i++) { |
| 50 | result = result.append(others.values[i]); |
| 51 | } |
| 52 | return result; |
| 53 | // Handled Edge Cases: Empty list of lists |
| 25 | 54 | } |
| 26 | 55 | |
| 27 | 56 | /** |
| 28 | | * @param {(any) => boolean} predicate |
| 29 | | * @return {List} |
| 57 | * Filters the list based on a predicate function |
| 58 | * @param {(any) => boolean} predicate - Function to test each element |
| 59 | * @return {List} A new list containing only elements that satisfy the predicate |
| 30 | 60 | */ |
| 31 | 61 | filter(predicate) { |
| 32 | | throw new Error('Remove this line and implement the function'); |
| 62 | // Edge Case: Filtering an empty list should return an empty list |
| 63 | if (this.values.length === 0) { |
| 64 | return new List([]); |
| 65 | } |
| 66 | |
| 67 | const filtered = []; |
| 68 | for (let i = 0; i < this.values.length; i++) { |
| 69 | if (predicate(this.values[i])) { |
| 70 | filtered.push(this.values[i]); |
| 71 | } |
| 72 | } |
| 73 | return new List(filtered); |
| 74 | // Handled Edge Cases: Empty list, predicate that matches no elements, predicate that matches all elements |
| 33 | 75 | } |
| 34 | 76 | |
| 35 | 77 | /** |
| 36 | | * @param {(any) => any} expression |
| 37 | | * @return {List} |
| 78 | * Transforms each element using the provided function |
| 79 | * @param {(any) => any} expression - Function to transform each element |
| 80 | * @return {List} A new list with transformed elements |
| 38 | 81 | */ |
| 39 | 82 | map(expression) { |
| 40 | | throw new Error('Remove this line and implement the function'); |
| 83 | // Edge Case: Mapping over an empty list should return an empty list |
| 84 | if (this.values.length === 0) { |
| 85 | return new List([]); |
| 86 | } |
| 87 | |
| 88 | const mapped = []; |
| 89 | for (let i = 0; i < this.values.length; i++) { |
| 90 | mapped.push(expression(this.values[i])); |
| 91 | } |
| 92 | return new List(mapped); |
| 93 | // Handled Edge Cases: Empty list |
| 41 | 94 | } |
| 42 | 95 | |
| 43 | 96 | /** |
| 44 | | * @return {number} |
| 97 | * Returns the number of elements in the list |
| 98 | * @return {number} The length of the list |
| 45 | 99 | */ |
| 46 | 100 | length() { |
| 47 | | throw new Error('Remove this line and implement the function'); |
| 101 | // Edge Case: Length of empty list should be 0 |
| 102 | let count = 0; |
| 103 | for (let i = 0; i < this.values.length; i++) { |
| 104 | count++; |
| 105 | } |
| 106 | return count; |
| 107 | // Handled Edge Cases: Empty list |
| 48 | 108 | } |
| 49 | 109 | |
| 50 | 110 | /** |
| 51 | | * @param {(acc: any, el: any) => any} callback |
| 52 | | * @param {any} initial |
| 53 | | * @return {any} |
| 111 | * Folds the list from the left using a callback function and initial accumulator |
| 112 | * @param {(acc: any, el: any) => any} callback - Function to apply to accumulator and each element |
| 113 | * @param {any} initial - Initial value for the accumulator |
| 114 | * @return {any} The final accumulated value |
| 54 | 115 | */ |
| 55 | 116 | foldl(callback, initial) { |
| 56 | | throw new Error('Remove this line and implement the function'); |
| 117 | // Edge Case: Folding an empty list should return the initial value |
| 118 | if (this.values.length === 0) { |
| 119 | return initial; |
| 120 | } |
| 121 | |
| 122 | let accumulator = initial; |
| 123 | for (let i = 0; i < this.values.length; i++) { |
| 124 | accumulator = callback(accumulator, this.values[i]); |
| 125 | } |
| 126 | return accumulator; |
| 127 | // Handled Edge Cases: Empty list |
| 57 | 128 | } |
| 58 | 129 | |
| 59 | 130 | /** |
| 60 | | * @param {(acc: any, el: any) => any} callback |
| 61 | | * @param {any} initial |
| 62 | | * @return {any} |
| 131 | * Folds the list from the right using a callback function and initial accumulator |
| 132 | * @param {(acc: any, el: any) => any} callback - Function to apply to accumulator and each element |
| 133 | * @param {any} initial - Initial value for the accumulator |
| 134 | * @return {any} The final accumulated value |
| 63 | 135 | */ |
| 64 | 136 | foldr(callback, initial) { |
| 65 | | throw new Error('Remove this line and implement the function'); |
| 137 | // Edge Case: Folding an empty list should return the initial value |
| 138 | if (this.values.length === 0) { |
| 139 | return initial; |
| 140 | } |
| 141 | |
| 142 | let accumulator = initial; |
| 143 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 144 | accumulator = callback(accumulator, this.values[i]); |
| 145 | } |
| 146 | return accumulator; |
| 147 | // Handled Edge Cases: Empty list |
| 66 | 148 | } |
| 67 | 149 | |
| 68 | 150 | /** |
| 69 | | * @return {List} |
| 151 | * Reverses the order of elements in the list |
| 152 | * @return {List} A new list with elements in reverse order |
| 70 | 153 | */ |
| 71 | 154 | reverse() { |
| 72 | | throw new Error('Remove this line and implement the function'); |
| 155 | // Edge Case: Reversing an empty list should return an empty list |
| 156 | if (this.values.length === 0) { |
| 157 | return new List([]); |
| 158 | } |
| 159 | |
| 160 | const reversed = []; |
| 161 | for (let i = this.values.length - 1; i >= 0; i--) { |
| 162 | reversed.push(this.values[i]); |
| 163 | } |
| 164 | return new List(reversed); |
| 165 | // Handled Edge Cases: Empty list, single element list |
| 73 | 166 | } |
| 74 | 167 | } |