Add DeprecatedFFICommonJSModule error

errors/DeprecatedFFICommonJSModule.md

@@ -0,0 +1,45 @@
+# `DeprecatedFFICommonJSModule` Error
+
+## Example
+
+```javascript
+const mymodule = require('some-module')
+
+exports.myvar = mymodule.myvar
+...
+```
+
+## Cause
+
+This error occurs when CommonJS (ES5) is used in FFI instead of ES modules (ES6). Support for CommonJS support has been removed in v0.15.0 and all FFI need to be written as ES modules instead.
+
+## Fix
+
+- Change `require` to `import`: 
+
+    ```javascript
+    const mymodule = require('some-module')
+    ```
+  to
+    ```javascript
+    import mymodule from 'some-module'
+    ```
+- Change `exports.name = value;` to `export const name = value;`
+
+## Notes
+
+Various tools exist to migrate ES5 code to ES6 code automatically. 
+
+One tool we recommend is [lebab](https://github.com/lebab/lebab).
+You can do just that transformation with one of the following commands:
+```bash
+# replace all *.js files in the src directory by rewriting them from
+# commonjs modules to es modules
+lebab --replace src --transform commonjs
+
+# you can also provide glob patterns, if you would like
+lebab --replace 'src/js/**/*.jsx' --transform commonjs
+```
+
+The CommonJS → ES modules transform is considered unsafe, because there are some edge cases the tool is unable to handle. These are issues worth checking for in your updated code:
+https://github.com/lebab/lebab#unsafe-transforms