The first loading page is slow app and vender js taking long time?

Hi Team
First loading page taking around 60-90 sec to show the data.
I am checking this two files taking more time load
1.vendor.4cb59bbda465c391ae8e.js
2.app.4cb59bbda465c391ae8e.js
enable_gzip=true
My app.js size is 3.4 MB
and veder is 1.4 MB
how we can reduce the file size
Please suggest how to improve the performance.