How to use fzf to search within all lines of files (ignore newlines)?

The fzf examples wiki page describes how fzf can be used to fuzzy search within the content all the files of a directory. But in the examples from the wiki page, e.g. with ag --nobreak --nonumbers --noheading . | fzf the files are split up by their lines and each line is treated separately. For example a file: hello world wouldn't match the search term "hello world" because the search terms are in different lines. How can I use fzf so that it searches within the whole file and not only by lines?