JavaScript fundamental (ES6 Syntax): Replace all but the last number of characters with the specified mask character - w3resource
How to count the number of occurrences of a character in a string in JavaScript (JavaScript, string, development) - Quora
![JavaScript basic: Check a given string contains 2 to 4 numbers of a specified character - w3resource JavaScript basic: Check a given string contains 2 to 4 numbers of a specified character - w3resource](https://www.w3resource.com/w3r_images/javascript-basic-exercise-flowchart-35.png)
JavaScript basic: Check a given string contains 2 to 4 numbers of a specified character - w3resource
![Java Program to Count the Number of Lines, Words, Characters, and Paragraphs in a Text File - GeeksforGeeks Java Program to Count the Number of Lines, Words, Characters, and Paragraphs in a Text File - GeeksforGeeks](https://media.geeksforgeeks.org/wp-content/uploads/20211001002640/TestOutput.png)