CommonJS compatibility does not work as expected · Issue #3360 · google/closure-compiler (original) (raw)

The compiler puts each commonJs module into default property of the imported object.

// ecma import commonJs from './common-js'

console.log('requiring a common js from ecma:') console.log(commonJs)

Run the compiler

java -jar /Users/zavr/node_modules/google-closure-compiler-java/compiler.jar
--compilation_level ADVANCED --language_out ECMASCRIPT_2017 --formatting PRETTY_PRINT
--process_common_js_modules --entry_point
example/commonjs/index.js --module_resolution NODE --js
example/commonjs/index.js example/commonjs/common-js.js example/commonjs/common-js2.js

Get the output

'use strict'; var a = () => { console.log("default common js export2"); }; a.named = () => { console.log("named common js export2"); }; var b = {default:() => { console.log("default common js export"); }}; b.default.named = () => { console.log("named common js export"); }; console.log("requiring a common js from common js:"); console.log(a); console.log("requiring a common js from ecma:"); console.log(b);

Execute the output

requiring a common js from common js: { [Function: a] named: [Function] } requiring a common js from ecma: { default: { [Function: default] named: [Function] } }

This does not make sense. I shouldn't write .default as confirmed here #3308. When it comes to Babel-compiled modules, it's a nightmare. Babel exports { default: code } itself, so the currently closure-compatible code becomes

import erte from '@a-la/fixture-babel'

console.log(erte.default.default()) console.log(erte.default.c()) console.log(erte.default.b())

And if you actually try to execute in with babel, you get

console.log(_.default.default.default());
                              ^

TypeError: Cannot read property 'default' of undefined

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