Rule fix: Add allowIds option to no-global-selector to allow global selector by ID

* Allow global selector by ID

Selection by ID is safe, we should allow it.  I believe that's what
was originally intended in this rule?

Should the same fix be applied to the `context` selector below?

* Adjust test to allow global ID selectors

* Make no-global-selector allowIds an option

Author: adamwight

docs/no-global-selector.md

@@ -1,12 +1,12 @@
 # no-global-selector
 
-Disallows global selectors which search the whole document. Encourages users to keep references to DOM nodes in memory, instead of selecting them from the DOM each time.
+Disallows global selectors which search the whole document. Encourages users to keep references to DOM nodes in memory, instead of selecting them from the DOM each time. Use the `allowIds` option to allow single ID selectors.
 
 ## Rule details
 
 ❌ The following patterns are considered errors:
 ```js
-$( '.div' );
+$( 'div' );
 $( '#id' );
 $( '.selector' );
 $( '.selector > .child' );
@@ -16,6 +16,12 @@ $( '.selector', null );
 $( '.selector', undefined );
 $( '.selector', $( '.context' ) );
 ```
+❌ With `[{"allowIds":true}]` options:
+```js
+$( '#id>div' );
+$( '#id~div' );
+$( '#id div' );
+```
 
 ✔️ The following patterns are not considered errors:
 ```js
@@ -37,6 +43,11 @@ $( undefined );
 $( false );
 $( '#' );
 ```
+✔️ With `[{"allowIds":true}]` options:
+```js
+$( '#id' );
+$( '#id-foo_bar1' );
+```
 ## Rule source
 
 * [rules/no-global-selector.js](../src/rules/no-global-selector.js)

src/rules/no-global-selector.js

@@ -4,14 +4,28 @@ const utils = require( '../utils.js' );
 
 // HTML regex (modified from jQuery)
 const rquickExpr = /^(?:\s*(<[\w\W]+>)[^>]*)$/;
+// ID patterns that return one DOM node
+const idPattern = /^#[^>~\s]+$/;
 
 module.exports = {
 	meta: {
 		type: 'suggestion',
 		docs: {
-			description: 'Disallows global selectors which search the whole document. Encourages users to keep references to DOM nodes in memory, instead of selecting them from the DOM each time.'
+			description: 'Disallows global selectors which search the whole document. ' +
+			'Encourages users to keep references to DOM nodes in memory, instead of selecting them from the DOM each time. ' +
+			'Use the `allowIds` option to allow single ID selectors.'
 		},
-		schema: []
+		schema: [
+			{
+				type: 'object',
+				properties: {
+					allowIds: {
+						type: 'boolean'
+					}
+				},
+				additionalProperties: false
+			}
+		]
 	},
 
 	create: function ( context ) {
@@ -26,10 +40,13 @@ module.exports = {
 					return;
 				}
 				const value = node.arguments[ 0 ].value;
+				const allowIds = context.options[ 0 ] && context.options[ 0 ].allowIds;
 				if (
 					typeof value !== 'string' ||
 					!value ||
-					value === '#' ) {
+					value === '#' ||
+					( allowIds && idPattern.test( value.trim() ) )
+				) {
 					return;
 				}
 

tests/rules/no-global-selector.js

@@ -16,6 +16,14 @@ ruleTester.run( 'no-global-selector', rule, {
 		'$(".selector", context)',
 		'$(".selector", "#")',
 		'$(".selector", [])',
+		{
+			code: '$("#id")',
+			options: [ { allowIds: true } ]
+		},
+		{
+			code: '$("#id-foo_bar1")',
+			options: [ { allowIds: true } ]
+		},
 		'$(function() {})',
 		// Variables could be a selector, but could equally be HTML or functions, so leave as valid
 		'$(variable)',
@@ -31,7 +39,7 @@ ruleTester.run( 'no-global-selector', rule, {
 	],
 	invalid: [
 		{
-			code: '$(".div")',
+			code: '$("div")',
 			errors: [ { message: error, type: 'CallExpression' } ]
 		},
 		{
@@ -65,6 +73,21 @@ ruleTester.run( 'no-global-selector', rule, {
 		{
 			code: '$(".selector", $(".context"))',
 			errors: [ { message: error, type: 'CallExpression' } ]
+		},
+		{
+			code: '$("#id>div")',
+			errors: [ { message: error, type: 'CallExpression' } ],
+			options: [ { allowIds: true } ]
+		},
+		{
+			code: '$("#id~div")',
+			errors: [ { message: error, type: 'CallExpression' } ],
+			options: [ { allowIds: true } ]
+		},
+		{
+			code: '$("#id div")',
+			errors: [ { message: error, type: 'CallExpression' } ],
+			options: [ { allowIds: true } ]
 		}
 	]
 } );