programming languages - How do I change file extension with javascript

Question

Does anyone know an easy way to change a file extension in Javascript?

For example, I have a variable with "first.docx" but I need to change it to "first.html".

question from:https://stackoverflow.com/questions/5953239/how-do-i-change-file-extension-with-javascript

Answer 1

This will change the string containing the file name;

let file = "first.docx";

file = file.substr(0, file.lastIndexOf(".")) + ".htm";

For situations where there may not be an extension:

let pos = file.lastIndexOf(".");
file = file.substr(0, pos < 0 ? file.length : pos) + ".htm";