Makefile

# A rough demo demo following the instructions 
# on https://docs.github.com/en/actions/tutorials/create-actions/create-a-javascript-action
#

define rollup_content =
import commonjs from "@rollup/plugin-commonjs";
import { nodeResolve } from "@rollup/plugin-node-resolve";

const config = {
        input: "index.js",
        output: {
                esModule: true,
                file: "dist/index.js",
                format: "es",
                sourcemap: true,
        },
        plugins: [commonjs(), nodeResolve({ preferBuiltins: true })],
};

export default config;
endef

export rollup_content

demo-cache demo-exec: package.json rollup.config.js
demo-cache demo-exec: node_modules/rollup/package.json
demo-exec: node_modules/@actions/exec/package.json
demo-cache: node_modules/@actions/cache/package.json

demo-exec:
        echo 'import * as exec from "@actions/exec";' > index.js
        npm exec -- rollup --config rollup.config.js

demo-cache:
        echo 'import * as cache from "@actions/cache";' > index.js
        npm exec -- rollup --config rollup.config.js

package.json: Makefile
        npm init -y
        jq '.type = "module"' <package.json >package.json.new
        mv package.json.new package.json

node_modules/rollup/package.json: Makefile
        npm install --save-dev rollup @rollup/plugin-commonjs @rollup/plugin-node-resolve

node_modules/@actions/exec/package.json: Makefile
        npm install @actions/exec

node_modules/@actions/cache/package.json: Makefile
        npm install @actions/cache

rollup.config.js: Makefile
        echo "$$rollup_content" > $@

test 1: make demo-exec

% make demo-exec
echo 'import * as exec from "@actions/exec";' > index.js
npm exec -- rollup --config rollup.config.js

index.js → dist/index.js...
created dist/index.js in 235ms

test 2 - make demo-cache

echo 'import * as cache from "@actions/cache";' > index.js
npm exec -- rollup --config rollup.config.js

index.js → dist/index.js...
[!] (plugin commonjs--resolver) RollupError: node_modules/@actions/cache/package.json (2:8): Expected ';', '}' or <eof> (Note that you need @rollup/plugin-json to import JSON files)
node_modules/@actions/cache/package.json (2:8)
1: {
2:   "name": "@actions/cache",
           ^
3:   "version": "4.1.0",
4:   "preview": true,
    at Object.getRollupError (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/parseAst.js:285:41)
    at ParseError.initialise (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:16064:40)
    at convertNode (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:17947:10)
    at convertProgram (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:17187:12)
    at Module.setSource (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:18935:24)
    at async ModuleLoader.addModuleSource (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:22581:13)
  [cause] RollupError: Expected ';', '}' or <eof>
      at Object.getRollupError (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/parseAst.js:285:41)
      at ParseError.initialise (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:16064:40)
      at convertNode (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:17947:10)
      at convertProgram (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:17187:12)
      at Module.setSource (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:18935:24)
      at async ModuleLoader.addModuleSource (/home/jls/projects/experiments/nodejs/gha-rollup/node_modules/rollup/dist/shared/rollup.js:22581:13)


make: *** [Makefile:32: demo-cache] Error 1