ES modules are already parsed in strict mode.

This reverts commit 7f0c07e.

Node.js loads JavaScript files with a .js extension as CommonJS modules unless they're within a directory with a `"type": "module"` package.json, in which case it loads them as ES modules.

Node.js ignores the package.json file of the output directory otherwise and loads .js files as CommonJS modules.

Node.js allows ES modules to import CommonJS modules by providing the module.exports object as their default export and named exports for statically discoverable properties of the module.exports object.

This has an unpleasant consequence for foreign imports: CommonJS exports named `default` are only available as the default property of their default export so a `default :: String` identifier imported from a CommonJS foreign module would actually have type `{ default :: String }`!

The require function and the exports object are not available in ES modules on Node.js.

…ations

This reverts commit 4976eee.

This reverts commit 6be0c52.

f58f5f0 'ExternsDiff: normalize type'

Fixes a bug where type synonym changes are incorrectly computed when diffing externs.

See https://github.com/zyla/purs-recompilation-repro for a reproducer of the bug.

Bug explanation: Externs files can have multiple entries with the same Ref, but the code in ExternsDiff assumed uniqueness. This led to buggy dependency graph construction.

The fix is to merge duplicate entries.