ack-grep show the matched files name only. Do not show the matched content

Both ack and grep have the -l option that shows only the filename. You can also use the -c to get a count of the matches in each file.

Note that if you're searching minified files, you may run into problems with ack because it specifically excludes many minified files. Run ack --dump | ack ignore to see what ack ignores.

The standard option grep -l (that is a lowercase L) could do this.

From the unix standard:

-l
    (The letter ell.) Write only the names of files containing selected
    lines to standard output. Pathnames are written once per file searched.
    If the standard input is searched, a pathname of (standard input) will
    be written, in the POSIX locale. In other locales, standard input may be
    replaced by something more appropriate in those locales.

Shameless stolen from this stackoverflow post.