Migrate code to use a global variable instead of linking your gatsby-config in your code/bundle

Author: halkeye

src/gatsby-ssr.js

@@ -0,0 +1,13 @@
+import React from "react"
+
+exports.onRenderBody = ({ setPostBodyComponents }, pluginOptions) => {
+  setPostBodyComponents([
+    React.createElement(
+      'script',
+      {
+        key: "gatsby-plugin-mailchimp",
+        dangerouslySetInnerHTML: { __html: `window.__GATSBY_PLUGIN_MAILCHIMP__ = ${JSON.stringify(pluginOptions)};` }
+      }
+    )
+  ])
+}

src/index.js

@@ -1,4 +1,3 @@
-import gatsbyConfig from '../../gatsby-config'
 import jsonp from 'jsonp'
 import { validate } from 'email-validator'
 
@@ -18,23 +17,6 @@ const subscribeEmailToMailchimp = url => (
   })
 )
 
-/*
- * parse the plugin options to use in our jsonp request
- */
-
-const getPluginOptions = () => {
-  // find gatsby-mailchimp plugin options (MC list settings)
-  const options = gatsbyConfig.plugins.find(
-    plugin => plugin.resolve === 'gatsby-plugin-mailchimp'
-  ).options
-
-  const isString = typeof options.endpoint === 'string'
-  if (!isString) {
-    throw `Mailchimp endpoint required and must be of type string. See repo README for more info.`
-  }
-  return options
-};
-
 /*
  * build a query string of MC list fields
  * ex: '&KEY1=value1&KEY2=value2'
@@ -65,7 +47,10 @@ const addToMailchimp = (email, fields) => {
   // generate Mailchimp endpoint for jsonp request
   // note, we change `/post` to `/post-json`
   // otherwise, Mailchomp returns an error
-  let {endpoint} = getPluginOptions()
+  let {endpoint} = window.__GATSBY_PLUGIN_MAILCHIMP__ || {};
+  if (!typeof endpoint === 'string') {
+    return Promise.reject(`Mailchimp endpoint required and must be of type string. See repo README for more info.`);
+  }
   endpoint = endpoint.replace(/\/post/g, '/post-json')
 
   const queryParams = `&EMAIL=${emailEncoded}${convertListFields(fields)}`