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Now talking about copy in the dockerfile,

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there is one extra,

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bit of configuration we can add to our project.

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At the moment this copy instruction copies everything

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in the folder where this Docker file lives,

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because I just have a dot here,

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which means everything.

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Previously, I also copied just package dot Jason

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to the working directory,

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but in this step we copy actually everything.

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Now this is something we can do,

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everything works, but we can also restrict

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what gets copied here.

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And we do this by adding a dot Docker ignore file here

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the dot at the beginning is important.

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If you know git this concept might be familiar to you

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with Git, which is a source control tool,

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has nothing to do with Docker.

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With Git we can add gitignore,

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to tell Git to which possibly existing folders and files

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in our project folder should not be committed to git.

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With Docker ignore,

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we can specify which folders and files,

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should not be copied by a copy instruction.

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And here in Docker ignore

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we could also add node modules to ensure,

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that if a node modules folder would exist here,

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which it doesn't,

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but which would be the case,

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if they would run npm install on my host machine,

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in this project folder,

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that such a folder is not getting copied into the image.

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Because if we would copy it in,

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if it would exist,

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we would overwrite the node modules folder

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which is created inside of the image

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with npm install.

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And that's bad,

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because our locally existing node modules folder

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could be outdated,

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could be missing important dependencies

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which we did add inside of the image,

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Or even if it is up to date,

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it simply makes that copy process take a bit longer.

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So that's why adding such a Docker ignore file,

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could make sense to ensure that certain folders or files

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in this case the node modules folder,

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are not getting copied

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into your image

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whenever you use the copy instruction.

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So that's why I'm adding it here,

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even though we don't strictly need it here.

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But again, in case I had a node modules folder,

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this ensures it's not getting copied into the image,

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but instead we stick to the one

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which is created inside of the image with npm install.