Skip to main content

Fibonacci In Javascript Using Generator Function and Iterable

Generating the Fibonacci sequence is usually demonstrated in computer science courses to show an implementation of a recursive function. Besides the recursive function, we can utilize the generator function in Javascript for generating the sequence. Let us take a look at a few methods that we can perform. For instance, we will create some functions to get the value of a certain position in the Fibonacci sequence. Then, we will measure up the performance to get solid ground on what we should choose in our application.

Recursive Function

This is the simplest method for getting the value in the sequence. We use 1, not 0, as starting position to make this function more human.

function getFibonacci1(pos) {
  if (pos === 1) {
    return 0;
  if (pos === 2) {
    return 1;
  return getFibonacci1(pos - 1) + getFibonacci1(pos - 2);

Generator Function

In this method, we create a generator function for generating sequence and the actual function for providing the result. The generator function results in an iterator that implements the next() method to iterate over the results.

function* fibonacci() {
  let a = 0;
  let b = 1;

  while (true) {
    yield a;
    [a, b] = [b, a + b];

export function getFibonacci2(pos) {
  const gen = fibonacci();

  for (let i = 1; i < pos; i++) {;


Iterable Object

We can also create an iterable object which implements a generator function as its property. We can iterate an iterable object using the for-of statement.

const fibonacciObj = {
  *[Symbol.iterator]() {
    let a = 0;
    let b = 1;

    while (true) {
      yield a;
      [a, b] = [b, a + b];

export function getFibonacci3(pos) {
  let count = 1;
  let result = 0;

  for (const val of fibonacciObj) {
    if (count === pos) {
      result = val;

  return result;

We start the test to get the value of the number at position 10. The result is as follows.

No. Recursive Generator Function Iterable Object
1 0.044599950313568 0.095099985599518 0.094399988651276
2 0.042400002479553 0.085600018501282 0.095099985599518
3 0.043699979782104 0.087499976158142 0.09799998998642
4 0.042400002479553 0.086300015449524 0.096100032329559
5 0.042699992656708 0.087100028991699 0.104199945926666
Average 0.043159985542297 0.088320004940033 0.097559988498688

It shows that the recursive method seems more superior to the rest. But. what if we try to get the value of the number at a higher position such as 40. The result is as follows.

No. Recursive Generator Function Iterable
1 682.451999962329 0.213900029659271 0.122600018978118
2 701.861900031566 0.204699993133544 0.121100008487701
3 667.377600014209 0.206699967384338 0.122200012207031
4 675.731999993324 0.218099951744079 0.126100003719329
5 659.384400010109 0.203800022602081 0.11540001630783
Average 677.361580002307 0.209439992904663 0.121480011940002

The result shows that recursion performance is very poor compared to other methods. The recursive method initiates a new function every time it is called. While the others basically only run a loop process. They only need chunks of time at the beginning of the process to set up the generator. The third method performs better because it only initiates the iterable object once in the process. While the second method still needs to reinitiate the generator function every time the main process is run.

In conclusion, we must be careful in utilizing recursive functions. It may consume a lot of our computing resources. Alternatively, the generator function may become another option in generating any kind of sequence in a Javascript program.


Popular posts from this blog

Setting Up Next.js Project With ESLint, Typescript, and AirBnB Configuration

If we initiate a Next.js project using the  create-next-app tool, our project will be included with ESLint configuration that we can apply using yarn run lint . By default, the tool installs eslint-config-next and extends next/core-web-vitals in the ESLint configuration. The Next.js configuration has been integrated with linting rules for React and several other libraries and tools. yarn create next-app --typescript For additional configuration such as AirBnB, it is also possible. First, we need to install the peer dependencies of eslint-config-airbnb . We also add support for Typescript using eslint-config-airbnb-typescript . yarn add --dev eslint-config-airbnb eslint-plugin-import eslint-plugin-jsx-a11y eslint-plugin-react eslint-plugin-react-hooks yarn add --dev eslint-config-airbnb-typescript @typescript-eslint/eslint-plugin @typescript-eslint/parser After that, we can update the .eslintrc.json file for the new configuration. { "extends": [ "airb

Rangkaian Sensor Infrared dengan Photo Dioda

Keunggulan photodioda dibandingkan LDR adalah photodioda lebih tidak rentan terhadap noise karena hanya menerima sinar infrared, sedangkan LDR menerima seluruh cahaya yang ada termasuk infrared. Rangkaian yang akan kita gunakan adalah seperti gambar di bawah ini. Pada saat intensitas Infrared yang diterima Photodiode besar maka tahanan Photodiode menjadi kecil, sedangkan jika intensitas Infrared yang diterima Photodiode kecil maka tahanan yang dimiliki photodiode besar. Jika  tahanan photodiode kecil  maka tegangan  V- akan kecil . Misal tahanan photodiode mengecil menjadi 10kOhm. Maka dengan teorema pembagi tegangan: V- = Rrx/(Rrx + R2) x Vcc V- = 10 / (10+10) x Vcc V- = (1/2) x 5 Volt V- = 2.5 Volt Sedangkan jika  tahanan photodiode besar  maka tegangan  V- akan besar  (mendekati nilai Vcc). Misal tahanan photodiode menjadi 150kOhm. Maka dengan teorema pembagi tegangan: V- = Rrx/(Rrx + R2) x Vcc V- = 150 / (150+10) x Vcc V- = (150/160) x 5

Itachi Uchiha

The Real Hero of Konoha

How To Use Git in Netbeans

Git is a popular version control application nowadays. Recently I have created a note about its differences with SVN and how to use it in Eclipse . There are many Git client tools. But I just want to show how to use Netbeans built-in Git tools. It makes the development process easier because it has been integrated with the IDE. Create Remote Git Repository We need a remote Git repository so everyone can store or receive any revision or updated files through the networks. We can set up our own Git server or use a public Git server like Github . In this note, I use Github. 1. Create an account in Github and create an empty Git repository Create an empty public repository in Github 2. Get the remote repository link Your Github Repository URL Create a New Project in Netbeans and Create Local Git Repository After we have a remote Git repository, we can create a project stored in the remote repository. We also need to create a local repository before we can push

Raspberry Pi Bluetooth Connection

Raspberry Pi 3 provides a built-in Bluetooth module. The latest Raspbian has been bundled with tools for enabling Bluetooth connection. The Bluetooth icon will be shown up on the top right corner of the desktop. It's a tool to discover available Bluetooth devices and connect Pi with Bluetooth devices. It is easy to connect any Bluetooth-enabled electronic device with Pi. But, sometimes Pi will fail to connect, especially for Bluetooth device that has no standardized services. From a terminal, we can use the  bluetoothctl tool to scan and connect with a Bluetooth device. You should make sure that the BlueZ protocol stack has been installed by running $ apt-get install bluez Run bluetoothctl to enter the tool command window Turn the power on by running power on (Optional) You can set AutoEnable=true in /etc/bluetooth/main.conf if you want to make the Bluetooth auto power-on after reboot. Run devices to see which devices have been paired Run scan on if your desired d

Configuring Swap Memory on Ubuntu Using Ansible

If we maintain a Linux machine with a low memory capacity while we are required to run an application with high memory consumption, enabling swap memory is an option. Ansible can be utilized as a helper tool to automate the creation of swap memory. A swap file can be allocated in the available storage of the machine. The swap file then can be assigned as a swap memory. Firstly, we should prepare the inventory file. The following snippet is an example, you must provide your own configuration. [server] [server:vars] ansible_user=root ansible_ssh_private_key_file=~/.ssh/id_rsa Secondly, we need to prepare the task file that contains not only the tasks but also some variables and connection information. For instance, we set /swapfile  as the name of our swap file. We also set the swap memory size to 2GB and the swappiness level to 60. - hosts: server become: true vars: swap_vars: size: 2G swappiness: 60 For simplicity, we only check the exi