|No such thing as a small change|
Yeah, node.js, that's true... But that's when JS is running on the server. Normally, in most cases, JS is running on the client side inside the web browser. And when you're inside the web browser, you cannot access the local file system.
The vec() function in perl allows a programmer to modify one character of a giant string by overwriting the string. Example: vec($a, 20000, 8) = 32; In perl, this operation is extremely fast, because all you do is modify one byte in the memory.