How can PHP developers avoid adding unnecessary spaces or characters when writing data to a file?

PHP developers can avoid adding unnecessary spaces or characters when writing data to a file by using the `FILE_IGNORE_NEW_LINES` flag with the `file_put_contents()` function. This flag prevents the function from adding a newline character at the end of the file, which can cause extra spaces or characters to be added unintentionally.

$data = "Hello, World!";
file_put_contents('file.txt', $data, FILE_IGNORE_NEW_LINES);