[BUG]: ExportCollapse undefined call expression

[wridgeu]

Hi,

I stumbled over the following issue which, while easy to resolve in many ways on the app dev side, I thought I might report - just in case.

It is triggered when all of the following are true:

• The module has a default export and at least one named export.
• The default export resolves to a value built from Object.assign(Object.create(null), { ... }).
• Export collapsing is active (default behavior unless noExportCollapse is enabled).

The stack trace pointed to

• node_modules/babel-plugin-transform-modules-ui5/dist/modules/helpers/exports.js:77

But could be traced back to actually being a result of:

export function getPropertiesOfObjectAssignOrExtendHelper(
  node,
  blockScopeNode
) {
  // Check all the args and recursively try to get props of identifiers (although they may be imported)
  return flatten(
    node.arguments.map((arg) => {
      if (t.isObjectExpression(arg)) {
        return arg.properties;
      }
      if (t.isIdentifier(arg)) {
        // Recursive, although props will be empty if arg is an imported object
        return getOtherPropertiesOfIdentifier(blockScopeNode, arg.name);
      }
      return [];     // possible fix
    })
  ).filter(Boolean); // possible fix
}

In here, the Object.create(null) of Object.assign(Object.create(null), { ... }) seems to add an undefined entry which later on fails in exports.js during:

if (!defaultExportProperty.key) {
  continue;
}

Quick Repro

const babel = require("@babel/core");
const plugin = require("babel-plugin-transform-modules-ui5");

const cases = [
  [
    "withAsConst",
    "const test=Object.assign(Object.create(null),{a:1}); export const TEST_CONSTANT='test' as const; export default test;",
  ],
  [
    "withoutAsConst",
    "const test=Object.assign(Object.create(null),{a:1}); export const TEST_CONSTANT='test'; export default test;",
  ],
  [
    "typeLiteralAnnotation",
    "const test=Object.assign(Object.create(null),{a:1}); export const TEST_CONSTANT:'test'='test'; export default test;",
  ],
  ["noNamedExport", "const test=Object.assign(Object.create(null),{a:1}); export default test;"],
  [
    "safeObjectAssign",
    "const test=Object.assign({}, {a:1}); export const TEST_CONSTANT='test' as const; export default test;",
  ],
  [
    "twoStepCreateAssign",
    "const test=Object.create(null); Object.assign(test,{a:1}); export const TEST_CONSTANT='test' as const; export default test;",
  ],
];

for (const [name, code] of cases) {
  try {
    babel.transformSync(code, {
      filename: `${name}.ts`,
      plugins: [plugin],
      parserOpts: { plugins: ["typescript"] },
    });
    console.log(`${name}: OK`);
  } catch (error) {
    console.log(`${name}: FAIL -> ${String(error.message).split("\n")[0]}`);
  }
}

One remark on contribution: I ran into several issues on windows in plenty of places in this repo, so I stopped bothering for now. I initially wanted to add a PR as well, as it is a seemingly small change/fix. But I also didn't want to overhaul half the repository just to get things working. I'm open though, maybe it was my mistake/error after all and maybe this isn't even a real issue that needs fixing. So an issue might even be the better way to go in the end. :)

BR