ncc is unable to import third party modules via "import". Cannot read properties of undefined

[mavendonovanhubbard]

I have the following typescript code:

import core from "@actions/core";
console.log(core.getInput("foo"));

Building it with ncc build src/main.ts -o dist and executing it returns

console.log(core_1.default.getInput("foo"));
                           ^

TypeError: Cannot read properties of undefined (reading 'getInput')

I've found that by converting the import statement to a require statement, const core = require("@actions/core"); the code executes successfully.

I've also found that core, first-party node modules like fs can be imported via an import statement as well as my local code while any third-party modules I tried have the above error.

I'm running ncc version 0.38.0
Here is my tsconfig.json file:

{
  "compilerOptions": {
    "target": "es2015",
    "module": "commonjs",
    "moduleResolution": "node",
    "outDir": "./dist/",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "skipLibCheck": true
  }
}

edit: corrected the ncc version number.

[mavendonovanhubbard]

The solution was to import the library with a *.

import * as core from "@actions/core"

This is described here: https://stackoverflow.com/questions/65227202/github-actions-how-to-work-with-typescript and is an example in the official documentation here. https://github.com/actions/typescript-action