When using container image "jenkins-agent-nodejs-8-rhel7", the npm executable isn't available at build time

Issue

When creating the following docker file from image jenkins-agent-nodejs-8-rhel7:

FROM registry.redhat.io/openshift3/jenkins-agent-nodejs-8-rhel7
RUN npm

The build doesn't succeed because It doesn't have the npm executable in the PATH:

$ docker build .
Sending build context to Docker daemon 2.048 kB
Step 1/2 : FROM registry.redhat.io/openshift3/jenkins-agent-nodejs-8-rhel7
 ---> dcc6983d8503
Step 2/2 : RUN npm
 ---> Running in 7bc4975f9676

/bin/sh: npm: command not found
The command '/bin/sh -c npm' returned a non-zero code: 127