Core: Migrate from AMD to ES modules 🎉

Migrate all source AMD modules to ECMAScript modules. The final bundle
is compiled by a custom build process that uses Rollup under the hood.

Test files themselves are still loaded via RequireJS as that has to work in
IE 11.

Tests can now be run in "Load as modules" mode which replaces the previous
"Load with AMD" option. That option of running tests doesn't work in IE
and Edge as it requires support for dynamic imports.

Some of the changes required by the migration:
* check `typeof` of `noGlobal` instead of using the variable directly
  as it's not available when modules are used
* change the nonce module to be an object as ECMASscript module exports
  are immutable
* remove some unused exports
* import `./core/parseHTML.js` directly in `jquery.js` so that it's not
  being cut out when the `ajax` module is excluded in a custom compilation

Closes gh-4541

4 files changed, 10 insertions, 29 deletions

diff --git a/src/data/Data.js b/src/data/Data.js
index c94480fcd..556f4e39c 100644
--- a/src/data/Data.js
+++ b/src/data/Data.js
@@ -1,11 +1,7 @@
-define( [
-	"../core",
-	"../core/camelCase",
-	"../var/rnothtmlwhite",
-	"./var/acceptData"
-], function( jQuery, camelCase, rnothtmlwhite, acceptData ) {
-
-"use strict";
+import jQuery from "../core.js";
+import camelCase from "../core/camelCase.js";
+import rnothtmlwhite from "../var/rnothtmlwhite.js";
+import acceptData from "./var/acceptData.js";
 
 function Data() {
 	this.expando = jQuery.expando + Data.uid++;
@@ -158,5 +154,4 @@ Data.prototype = {
 	}
 };
 
-return Data;
-} );
+export default Data;
diff --git a/src/data/var/acceptData.js b/src/data/var/acceptData.js
index e00f7538b..4fc47b30a 100644
--- a/src/data/var/acceptData.js
+++ b/src/data/var/acceptData.js
@@ -1,11 +1,7 @@
-define( function() {
-
-"use strict";
-
 /**
  * Determines whether an object can have data
  */
-return function( owner ) {
+export default function( owner ) {
 
 	// Accepts only:
 	//  - Node
@@ -15,5 +11,3 @@ return function( owner ) {
 	//    - Any
 	return owner.nodeType === 1 || owner.nodeType === 9 || !( +owner.nodeType );
 };
-
-} );
diff --git a/src/data/var/dataPriv.js b/src/data/var/dataPriv.js
index 72713c88c..94ea1190e 100644
--- a/src/data/var/dataPriv.js
+++ b/src/data/var/dataPriv.js
@@ -1,7 +1,3 @@
-define( [
-	"../Data"
-], function( Data ) {
-	"use strict";
+import Data from "../Data.js";
 
-	return new Data();
-} );
+export default new Data();
diff --git a/src/data/var/dataUser.js b/src/data/var/dataUser.js
index 72713c88c..94ea1190e 100644
--- a/src/data/var/dataUser.js
+++ b/src/data/var/dataUser.js
@@ -1,7 +1,3 @@
-define( [
-	"../Data"
-], function( Data ) {
-	"use strict";
+import Data from "../Data.js";
 
-	return new Data();
-} );
+export default new Data();