Why ?

to reduce time you spent waiting your docker image is being built.

How to use?

• Install as a dev dependency

npm i -d package-light

or

yarn add --dev package-light

• Add to your .git-ignore file

package-light.json
package-light-lock.json

• Add pre script for building docker image npx package-light which generate package-light.json and package-light-lock.json in case your use npm.

Example

somewhere in your package.json

"scripts": {
"prebuild:docker": "npx package-light",             // generate `package-light.json` and `package-light-lock.json` (if needed)
"build:docker": "docker build -t my-image-tag .",   // your command to build docker image
}

Dockerfile example

npm

FROM node:12.13

# Install app dependencies
COPY ./package-light.json ./package.json
COPY ./package-light-lock.json ./package-lock.json
RUN npm i
## <-- this layer is cached until your dependencies change

# App source
COPY . .
# do your stuff here

yarn

FROM node:12.13

# Install app dependencies
COPY package-light.json package.json
COPY yarn.lock ./
RUN yarn
## <-- this layer is cached until your dependencies change
# App source
COPY . .
# do your stuff here

This will greatly help to cache dependencies layer. After dependencies are installed you should copy the rest files and may override package-light.json with original package.json you may change your scripts, package version or other fields in your package json, it does not matter, dependencies layer remain unchanged.

// TODO:

• add example for react-create-app
• add example for express app