Fix gatsby-plugin-react-helmet for v6.0.0

[Ehesp]

Description

In version 6.0.0 of react-helmet, the default export has been removed. There is now only a named export, e.g.

import { Helmet } from 'react-helmet';

In v5.x.x, both a default export and named are exported. Change is here:

nfl/react-helmet@20ea385#diff-cc54072daf5278847980b841520c8fffL287

This is a backwards compatible change. v5 has an annoying bug (nfl/react-helmet#373) which v6 seems to fix.

[DSchau]

Looks good to me. Thanks for addressing this!

[DSchau]

I can't actually seem to get this to successfully build with gatsby-default-starter, the changes in this PR, and then react-helmet@6 (currently just a beta?).

error Building static HTML for pages failed

See our docs page on debugging HTML builds for help https://gatsby.app/debug-html

   8 | 	else
   9 | 		root["lib"] = factory(root["@reach/router"], root["core-js/modules/es6.array.iterator"], root["core-js/modules/es6.array.sort"], root["core-js/modules/es6.function.name"], root["core-js/modules/es6.map"], root["core-js/modules/es6.object.assign"], root["core-js/modules/es6.regexp.constructor"], root["core-js/modules/es6.regexp.split"], root["core-js/modules/es6.regexp.to-string"], root["core-js/modules/es6.string.ends-with"], root["core-js/modules/es6.string.iterator"], root["core-js/modules/web.dom.iterable"], root["fs"], root["lodash"], root["path"], root["react"], root["react-dom/server"], root["react-helmet"]);
> 10 | })(this, function(__WEBPACK_EXTERNAL_MODULE__reach_router__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_array_iterator__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_array_sort__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_function_name__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_map__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_object_assign__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_regexp_constructor__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_regexp_split__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_regexp_to_string__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_string_ends_with__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_es6_string_iterator__, __WEBPACK_EXTERNAL_MODULE_core_js_modules_web_dom_iterable__, __WEBPACK_EXTERNAL_MODULE_fs__, __WEBPACK_EXTERNAL_MODULE_lodash__, __WEBPACK_EXTERNAL_MODULE_path__, __WEBPACK_EXTERNAL_MODULE_react__, __WEBPACK_EXTERNAL_MODULE_react_dom_server__, __WEBPACK_EXTERNAL_MODULE_react_helmet__) {
     |  ^
  11 | return 


  WebpackError: Invariant Violation: Minified React error #130; visit https://reactjs.org/docs/error-decoder.html?inv

I'll investigate this a bit further.

[DSchau]

Yeah - I can't seem to get this to build whatsoever.

Did you have any luck? Simply updating to [email protected] seems to break the build, even with this plugin's changes. In fact, it seems to fail before it even invokes the SSR APIs

Ha - would have to change the src/ directory to reflect this new pattern too 🙃

[DSchau]

OK! Able to validate this finally.

We'll have to make changes to the starters since they'll be incompatible with react-helmet@6 using the default export.

Before we get this merged, we should probably also tweak some documentation. I'll take a look at that and PR to this branch if that's alright!

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Thanks again!

[Ehesp]

Hey sorry was in a rush yesterday. Yeah 6.0 is in beta but there was a very annoying issue it fixed. Thanks for sorting 👍