Building Enterprise JavaScript Applications

Taking advantage of the cache

At the moment, we are copying our entire application code, installing its dependencies, and then building the application.

But what if I make changes to my application code, but do not introduce any new dependencies? In our current approach, we’d have to run all three steps again, and the RUN ["yarn"] step is likely going to take a long time as it has to download thousands of files:

COPY --chown=node:node . .RUN ["yarn"]RUN ["yarn", "run", "build"]

Fortunately, Docker implements a clever caching mechanism. Whenever Docker generates an image, it stores the underlying layers in the filesystem. When Docker is asked to build a new image, instead of blindly following the instructions again, Docker will check its existing ...