Build: Correct code indentations based on jQuery Style Guide

1. Correct code indentations based on jQuery Style Guide
   (contribute.jquery.org/style-guide/js/#spacing).
2. Add rules to "src/.eslintrc.json" to enable "enforcing consistent
   indentation", with minimal changes to the current code.

Closes gh-4672

src/.eslintrc.json

@@ -12,7 +12,10 @@
 
 	"rules": {
 		"import/extensions": [ "error", "always" ],
-		"import/no-cycle": "error"
+		"import/no-cycle": "error",
+		"indent": [ "error", "tab", {
+			"outerIIFEBody": 0
+		} ]
 	},
 
 	"overrides": [
@@ -23,7 +26,17 @@
 				"sourceType": "script"
 			},
 			"rules": {
-				"no-unused-vars": "off"
+				"no-unused-vars": "off",
+				"indent": [ "error", "tab", {
+
+					// Unlike other codes, "wrapper.js" is implemented in UMD.
+					// So it required a specific exception for jQuery's UMD
+					// Code Style. This makes that indentation check is not
+					// performed for 1 depth of outer FunctionExpressions
+					"ignoredNodes": [
+						"Program > ExpressionStatement > CallExpression > FunctionExpression > *"
+					]
+				} ]
 			},
 			"globals": {
 				"jQuery": false,

src/ajax.js

@@ -45,7 +45,8 @@ var
 
 	// Anchor tag for parsing the document origin
 	originAnchor = document.createElement( "a" );
-	originAnchor.href = location.href;
+
+originAnchor.href = location.href;
 
 // Base "constructor" for jQuery.ajaxPrefilter and jQuery.ajaxTransport
 function addToPrefiltersOrTransports( structure ) {

src/ajax/xhr.js

@@ -10,7 +10,7 @@ var xhrSuccessStatus = {
 
 	// File protocol always yields status code 0, assume 200
 	0: 200
-	};
+};
 
 jQuery.ajaxTransport( function( options ) {
 	var callback;

src/core.js

@@ -405,9 +405,9 @@ if ( typeof Symbol === "function" ) {
 
 // Populate the class2type map
 jQuery.each( "Boolean Number String Function Array Date RegExp Object Error Symbol".split( " " ),
-function( _i, name ) {
+	function( _i, name ) {
 		class2type[ "[object " + name + "]" ] = name.toLowerCase();
-} );
+	} );
 
 function isArrayLike( obj ) {
 

src/deprecated/event.js

@@ -28,7 +28,8 @@ jQuery.fn.extend( {
 	}
 } );
 
-jQuery.each( ( "blur focus focusin focusout resize scroll click dblclick " +
+jQuery.each(
+	( "blur focus focusin focusout resize scroll click dblclick " +
 	"mousedown mouseup mousemove mouseover mouseout mouseenter mouseleave " +
 	"change select submit keydown keypress keyup contextmenu" ).split( " " ),
 	function( _i, name ) {
@@ -39,4 +40,5 @@ jQuery.each( ( "blur focus focusin focusout resize scroll click dblclick " +
 				this.on( name, null, data, fn ) :
 				this.trigger( name );
 		};
-	} );
+	}
+);

src/dimensions.js

@@ -6,8 +6,11 @@ import "./css.js";
 
 // Create innerHeight, innerWidth, height, width, outerHeight and outerWidth methods
 jQuery.each( { Height: "height", Width: "width" }, function( name, type ) {
-	jQuery.each( { padding: "inner" + name, content: type, "": "outer" + name },
+	jQuery.each( {
-		function( defaultExtra, funcName ) {
+		padding: "inner" + name,
+		content: type,
+		"": "outer" + name
+	}, function( defaultExtra, funcName ) {
 
 		// Margin is only for outerHeight, outerWidth
 		jQuery.fn[ funcName ] = function( margin, value ) {

src/effects.js

@@ -511,6 +511,7 @@ jQuery.fn.extend( {
 					anim.stop( true );
 				}
 			};
+
 		doAnimation.finish = doAnimation;
 
 		return empty || optall.queue === false ?

src/event/trigger.js

@@ -99,9 +99,7 @@ jQuery.extend( jQuery.event, {
 				special.bindType || type;
 
 			// jQuery handler
-			handle = (
+			handle = ( dataPriv.get( cur, "events" ) || Object.create( null ) )[ event.type ] &&
-					dataPriv.get( cur, "events" ) || Object.create( null )
-				)[ event.type ] &&
 				dataPriv.get( cur, "handle" );
 			if ( handle ) {
 				handle.apply( cur, data );

src/selector.js

@@ -602,9 +602,11 @@ Expr = jQuery.expr = {
 		TAG: function( nodeNameSelector ) {
 			var expectedNodeName = nodeNameSelector.replace( runescape, funescape ).toLowerCase();
 			return nodeNameSelector === "*" ?
+
 				function() {
 					return true;
-} :
+				} :
+
 				function( elem ) {
 					return nodeName( elem, expectedNodeName );
 				};

src/serialize.js

@@ -101,16 +101,14 @@ jQuery.fn.extend( {
 			// Can add propHook for "elements" to filter or add form elements
 			var elements = jQuery.prop( this, "elements" );
 			return elements ? jQuery.makeArray( elements ) : this;
-		} )
+		} ).filter( function() {
-		.filter( function() {
 			var type = this.type;
 
 			// Use .is( ":disabled" ) so that fieldset[disabled] works
 			return this.name && !jQuery( this ).is( ":disabled" ) &&
 				rsubmittable.test( this.nodeName ) && !rsubmitterTypes.test( type ) &&
 				( this.checked || !rcheckableType.test( type ) );
-		} )
+		} ).map( function( _i, elem ) {
-		.map( function( _i, elem ) {
 			var val = jQuery( this ).val();
 
 			if ( val == null ) {