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Recursion in JS
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| // Recursion fundamentals: Counting down. | |
| function countDown(num) { | |
| console.log(num); | |
| if (num > 1) { | |
| countDown(num - 1); | |
| } | |
| } | |
| countDown(5); | |
| // Summing array elements | |
| function sum(elems) { | |
| if (elems.length === 0) { | |
| return 0; | |
| } else { | |
| const [head, ...rest] = elems; | |
| return head + sum(rest); | |
| } | |
| } | |
| console.log(sum([1, 2, 3, 4, 5])); | |
| // Calculating the power: 4^4 | |
| function power(num, pow) { | |
| if (pow == 1) { | |
| return num; | |
| } else { | |
| return num * power(num, pow - 1); | |
| } | |
| } | |
| console.log(power(4, 4)); | |
| // Calculating factorial: 5! (5 * 4 * 3 * 2 * 1) | |
| function factorial(num) { | |
| if (num <= 1) { | |
| return 1; | |
| } else { | |
| return num * factorial(num - 1); | |
| } | |
| } | |
| console.log(factorial(5)); | |
| // Ughhhh fibonacci kill me now | |
| // 0, 1, 1, 2, 3, 5, 8, 13, 21 | |
| function fibonacci(rem, acc = [0, 1]) { | |
| if (rem <= 2) { | |
| return acc; | |
| } else { | |
| const [second, last] = acc.slice(-2); | |
| return fibonacci(rem - 1, [...acc, second + last]); | |
| } | |
| } | |
| console.log(fibonacci(15)); | |
| // Trees! ☕️ | |
| const root = { | |
| node: "arabica", | |
| children: [ | |
| { node: "heirloom", children: [] }, | |
| { | |
| node: "bourbon", | |
| children: [ | |
| { node: "caturra", children: [] }, | |
| { node: "mokka", children: [] }, | |
| ], | |
| }, | |
| { | |
| node: "typica", | |
| children: [ | |
| { node: "kona", children: [] }, | |
| { node: "java", children: [] }, | |
| ], | |
| }, | |
| ], | |
| }; | |
| function print({ node, children }) { | |
| console.group(node); | |
| children.forEach((child) => print(child)); | |
| console.groupEnd(node); | |
| } | |
| print(root); |
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