CODEWITHSUNDEEP
ecmascript-6babeljs
Nikos
Nikos

Reputation: 7552

Babel error: Class constructor Foo cannot be invoked without 'new'

I am using babel to transpile.

I have class BaseComponent which is extended by class Logger.

When I run new Logger() in the browser, I am getting this error

Class constructor BaseComponent cannot be invoked without 'new'

the code that throws this is:

var Logger = function (_BaseComponent) {
  _inherits(Logger, _BaseComponent);

  function Logger() {
    _classCallCheck(this, Logger);

    return _possibleConstructorReturn(this, Object.getPrototypeOf(Logger).call(this, "n")); //throws here
  }

Upvotes: 13

Views: 9834

Answers (2)

Paulo Alexandre
Paulo Alexandre

Reputation: 902

Another solution is to include { exclude: ["transform-es2015-classes"] } in .babelrc

presets: [
   ["env", { exclude: ["transform-es2015-classes"] }]
]

UPDATE: In the latest version of "env" preset plugin names have changed (e.g. it's now "transform-classes"). Use the "debug" option to inspect which plugins are included.

Upvotes: 12

loganfsmyth
loganfsmyth

Reputation: 161467

Due to the way ES6 classes work, you cannot extend a native class with a transpiled class. If your platform supports native classes, my recommendation would be, instead of using the preset es2015, use es2015-node5, assuming you're on Node 5. That will cause Babel to skip compiling of classes so that your code uses native classes, and native classes can extend other native classes.

Upvotes: 14

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