Azure DevOps Extension Bundler - shelljs POC

This is a POC repository to showcase an existing issue when bundling tasks for Azure DevOps using the azure-pipelines-task-lib@4.12.1 library and a workaround which keeps your task size small (which is likely why you are already bundling your task code).

The problem

The shelljs library uses dynamic require() which makes esbuild unable to tree-shake correctly. If you are bundling your task with

npx esbuild task.js --platform=node --bundle --outfile=out/task.js
node out/task.js

You would get an error

/.../azure-devops-extension-bundler-shelljs-poc/out/task.js:10
  throw new Error("Module not found in bundle: " + path);
  ^

Error: Module not found in bundle: ./src/cat

You need to put shelljs as an external lib for esbuild:

npx esbuild task.js --platform=node --external:shelljs --bundle --outfile=out/task.js

But shelljs is required in the root of azure-pipelines-task-lib/task, so you'll likely get another error:

Error: Cannot find module 'shelljs'

The workaround

shelljs is required by azure-pipelines-task-lib/task but never used if you are not directly using a function which uses it (most arn't). In this case, you can create an empty file under node_modules/shelljs/index.js which will let the require('shelljs') successfully complete with an undefined value.

POC

Run run.sh to run the workaround.

Questions

If you have questions, or if you found a better solution for this problem, please open an issue to discuss about it.