How to generate sha1('string') in ionic 3?

Friends,

I saw the installation of sha1 can done in ionic 3 as mentioned in URL : sha1 installation

I need to do following thing using sha1

Suppose my strings are string1=1, string2=56, string3=‘E#234ops’

then how I calculate sha1(string1+string2+strring3)

please advise asap

Thanks
Anes