I was following the Tour of Heroes Tutorial and in the HTTP section (part 8) I followed the instructions to install angular-in-memory-web-api with npm install angular-in-memory-web-api --save. This installed version 0.6.0 for me and it appears to be incompatible with angular 5 and rxjs 5. This caused the tutorial application to stop working. It took a while to track down the problem and fix by going down to version 0.5.4 of angular-in-memory-web-api. If other people are experiencing this it may make the HTTP section of the tutorial confusing.