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Commit 9362b78

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get extension from a file name
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‎L-B/0026 FileExtension/FileExtension.js

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function extractFileExtension(fileName) {
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// Split the file name into an array of strings at the dot character.
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const splitFileName = fileName.split('.');
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// Check if the split file name array has more than one element.
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if (splitFileName.length > 1) {
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// Get the last element in the array, which is the file extension.
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const fileExtension = splitFileName.pop();
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// Return the file extension.
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return fileExtension;
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}
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// The file name does not have an extension, so return an empty string.
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return '';
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}
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module.exports = extractFileExtension;
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const extractFileExtension = require('./FileExtension')
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describe('extractFileExtension', () => {
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it('should return the file extension when given a valid file name', () => {
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expect(extractFileExtension('example.txt')).toBe('txt');
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expect(extractFileExtension('document.docx')).toBe('docx');
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expect(extractFileExtension('image.jpg')).toBe('jpg');
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});
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it('should return an empty string when given a file name without an extension', () => {
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expect(extractFileExtension('README')).toBe('');
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expect(extractFileExtension('LICENSE')).toBe('');
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});
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it('should return an empty string when given an empty string', () => {
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expect(extractFileExtension('')).toBe('');
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});
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});
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/*
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test output:
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PASS ./FileExtension.test.js
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extractFileExtension
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√ should return the file extension when given a valid file name (4 ms)
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√ should return an empty string when given a file name without an extension (1 ms)
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√ should return an empty string when given an empty string
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Test Suites: 1 passed, 1 total
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Tests: 3 passed, 3 total
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Snapshots: 0 total
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Time: 0.958 s, estimated 1 s
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Ran all test suites.
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*/
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/*
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Testing with Jest global installation:
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> npm install -g jest
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> jest
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*/

‎L-B/0026 FileExtension/README.md

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# Get the file extension
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## Problem
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Write a function that takes a string and returns the file extension, which is the string after the last dot (.) in the string. If there is no dot in the string, return undefined.
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## Solution
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```javascript
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function extractFileExtension(fileName) {
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// Split the file name into an array of strings at the dot character.
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const splitFileName = fileName.split(".");
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// Get the last element in the array, which is the file extension.
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const fileExtension = splitFileName.pop();
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// Return the file extension.
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return fileExtension;
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}
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```
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## How it works
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- The `extractFileExtension` function takes a string as an argument.
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- The `split` method is used to split the string into an array of strings at the dot character.
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- The `pop` method is used to get the last element in the array, which is the file extension.
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- The file extension is returned.
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## References
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- [String.prototype.split()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split)
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## Problem Added By
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- [GitHub](https://github.com/aladin002dz)
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## Contributing
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Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
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Please make sure to update tests as appropriate.

‎L-B/0026 FileExtension/jest.config.json

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{}

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