Closure-compiler: Losing type information - "Property get never defined on formData of type FormData"

[Datamance]

Hi all,

I'm getting some strange compiler warnings. It's like the compiler forgets the externs for FormData - see here:

[npm 04/13/17 2:30:27] nps-plugin/index.js:150: WARNING - Property get never defined on formData of type FormData
[npm 04/13/17 2:30:27]           this.userName || formData.get('user_name'),
[npm 04/13/17 2:30:27]                            ^^^^^^^^^^^^
[npm 04/13/17 2:30:27] 
[npm 04/13/17 2:30:27] nps-plugin/index.js:152: WARNING - Property get never defined on formData of type FormData
[npm 04/13/17 2:30:27]           formData.get('score'),
[npm 04/13/17 2:30:27]           ^^^^^^^^^^^^
[npm 04/13/17 2:30:27] 
[npm 04/13/17 2:30:27] nps-plugin/index.js:153: WARNING - Property get never defined on formData of type FormData
[npm 04/13/17 2:30:27]           this.productId || formData.get('product_id'),
[npm 04/13/17 2:30:27]                             ^^^^^^^^^^^^
[npm 04/13/17 2:30:27] 
[npm 04/13/17 2:30:27] nps-plugin/index.js:154: WARNING - Property get never defined on formData of type FormData
[npm 04/13/17 2:30:27]           formData.get('comments')));

I'm not sure if it's related, but the properties on the Form elements elements property seem to be obfuscated as well:

I have to use form.elements['score'].value rather than what I had before, which was form.elements.score.value. Come to think of it, since the "score" element is dynamically defined (and thusly the compiler'd have no way of preserving the token), I have no idea why that was working before...

Here's my compiler info:

VERSION: 20161201.0.0

FLAGS:
java -jar
node_modules/google-closure-compiler/compiler.jar
--js="nps-plugin/index.js"
--js="node_modules/google-closure-library/closure/goog/.js"
--js="!node_modules/google-closure-library/closure/goog/_test.js"
--dependency_mode=STRICT
--compilation_level=ADVANCED_OPTIMIZATIONS
--entry_point=lnkd.NpsPlugin
--output_wrapper="(function(){%output%})();"
--new_type_inf
--jscomp_warning=newCheckTypes
--jscomp_off=newCheckTypesExtraChecks
--hide_warnings_for=node_modules/google-closure-library/
--output_manifest="build/report/manifest.MF"
--js_output_file=nps-plugin.js

Let me know if you can help... thanks so much!

[dimvar]

Can you file an issue internally, with steps for me how to build your project and reproduce the error?

[Datamance]

@dimvar I don't work at Google anymore :)

[Datamance]

I can show you the code where it's happening though:

/**
 * Gets JSON:API compliant data.
 * @private
 */
lnkd.NpsPlugin.prototype.getJsonApiPostData_ = function() {
  var formData = new FormData(this.form);
  return JSON.stringify(
      new lnkd.NpsPlugin.NpsJsonApiData(
          this.userName || formData.get('user_name'),
          this.userKey,
          formData.get('score'),
          this.productId || formData.get('product_id'),
          formData.get('comments')));
};

[Datamance]

@dimvar just tried with the newest versions of the compiler (and library) as well (20170409.0.0). Same warnings.

[brad4d]

This is sounding familiar.
I believe I looked into, and thought I fixed, an issue where methods named get were incorrectly removed.

[brad4d]

I was thinking of the opposite problem, actually. #2132
@Datamance it would help a lot if you could show the definition of FormData.

[Datamance]

@brad4d FormData is a native web api

[ChadKillingsworth]

It looks like our externs may be missing definitions: https://github.com/google/closure-compiler/blob/8ac08c03cd695b84f8a79ac3a1338172df00003f/externs/browser/w3c_xml.js#L444

[dimvar]

@Datamance feel free to submit a PR with the missing extern definitions.

[Datamance]

I will try ASAP - it's possible I'll be able to fit something in on saturday. You guys will see it when it comes in!