dynamically-load-npm-dependencies

This repository is for a proof-of-concept showing it is possible to...

• Download an npm package, then require() and use it at runtime using Node.js.
• Download an npm package, then require() and use it in the jsii runtime for a jsii target language. In this case, Python was used.
• Use the same npm package in a network-restricted environment if it was installed in the consuming TS/JS project, before execution.
• Use the same npm package in a network-restricted environment if it's jsii target language version was installed in the consuming project. In this case, if it's Python version was installed before execution.

This repository has 3 subdirectories:

lazy-load-npm-packages-poc/: A jsii library containing the logic to dynamically load npm dependencies at runtime.

python-consumer/: A Python project that uses lazy-load-npm-packages-poc.

node-consumer/: A TypeScript project that uses lazy-load-npm-packages-poc.

Steps to build and test

Build & Package the jsii library

cd lazy-load-npm-packages-poc
npm run build && npm run package

Test Python consumer

Setup

cd python-consumer
python3 -m venv .env
source .env/bin/activate
pip install -r requirements.txt

Test with network

./index.py

Test without network

1. Clear npm cache, and install the Python version of the dependency.

npm cache clean --force
pip install aws-cdk.core

2. Turn your mac into airplane mode or turn off wi-fi.

3. For the npm version of the dependency to be available in the jsii runtime process, the Python library has to have been loaded/imported already. Add the following or something similar to ./index.py:

from aws_cdk.core import App

4. Run it.

./index.py

Test Node consumer

Setup

npm install
npx tsc

Test with network

node ./index.js

Test without network

1. Clear npm cache, and install the dependency you are trying to dynamically load.

npm cache clean --force
npm install @aws-cdk/core

2. Turn your mac into airplane mode or turn off wi-fi.

3. Run it.

node ./index.js