Revert "Merge pull request #206 from chaijs/koddsson/add-esm-guide"

This reverts commit 01eb070, reversing
changes made to 9fffbc6.

_guides/index.md

@@ -17,7 +17,6 @@ assertion styles.
 
 - [Install Chai]({{site.github.url}}/guide/installation/) in node, the browser, and other environments.
 - [Learn about styles]({{site.github.url}}/guide/styles/) that you can use to define assertions.
-- [Importing Chai, and using plugins]({{site.github.url}}/guide/using-chai-with-esm-and-plugins/) to learn how to use Chai with ESM and plugins.
 
 ## Making Plugins
 
@@ -27,76 +26,5 @@ than what is included, limited only by what you want to achieve. The Plugin API
 is also intended as a way to simplify testing by providing users a way to
 encapsulate common assertions for repeat use.
 
-### Exposing Globals in Plugins
-
-When creating a Chai plugin, it's possible to expose globals that can be used across multiple files. Here's how to do it sustainably:
-
-#### Good Practice
-
-Prefer exporting any global in the module record so it can be imported directly instead of adding it as a property in the chai object:
-
-```javascript
-// An example of a good plugin:
-
-export const myGlobal = {...};
-
-export default function myPlugin(chai, utils) {
-}
-```
-
-#### Potential Issues
-
-Avoid exposing globals only through `chai.use()` without making them available for import, as this can lead to issues when trying to use the global across multiple files:
-
-```javascript
-// An example of a plugin which may have issues:
-
-const myGlobal = {...};
-
-export default function myPlugin(chai, utils) {
-  chai.myGlobal = myGlobal;
-}
-```
-
-```javascript
-// Another example of a plugin which may have issues:
-
-export default function myPlugin(chai, utils) {
-  chai.myGlobal = {...};
-}
-```
-
-### Guard against multiple calls to `use(..)`
-
-In certain situations the `use(..)` function  could be called multiple times with your plugin. For a lot of plugins this won't be a issue but it's considered best practise to check if the plugin has been applied already.
-
-Here's a contrived example of how you might implement a check in your plugin but the actual implementation is left up to the plugin author.
-
-```js
-import * as chai from 'chai';
-
-let overwritten = false;
-
-function somePlugin(base) {
-  if (!overwritten) {
-    base.util.overwriteMethod(base.Assertion.prototype, "equal", function (_super) {
-      return function(...args) {
-        console.log("Called!"); // log something out
-
-        return _super.call(this, ...args);
-      };
-    });
-    overwritten = true;
-  }
-}
-
-chai.use(somePlugin);
-chai.use(somePlugin);
-
-chai.expect(123).to.equal(123); // Logs `Called!` only once
-```
-
-By following these guidelines, you can create Chai plugins that are easy to use and maintain.
-
 - [Core Plugin Concepts]({{site.github.url}}/guide/plugins/) covers the basics of using the Chai Plugin API.
 - [Building a Helper]({{site.github.url}}/guide/helpers/) is a walkthrough for writing your first plugin.