Fastest way to find substring in an array of objects

Having a little trouble determining the fastest way to do this.

So currently I have a series of objects as such:

0
bookingReference:"TRTIY"
customer:{title: " FRAU", initial: "S", lastName: "HEINRICH", mobileNumber: "NULL"}
customerVehicle:{registration: null}

1  
bookingReference:"ABC12"
customer:{title: "Mr", initial: "J", lastName: "Bloggs", mobileNumber: "0123456789"}
customerVehicle:{registration: "AB12 CDE"}

and want to filter out the results based on a keyword or substring. SO for example, I want to filter the result based on 'hein' which should return the first object because the customer last name is Heinrich.