feat: better require-closing-tags support (#188)

* add test case covering non-void self-closing tag when self-closing is enforced * don't close non-void elements * add test case covering math self close exception * clarify names * re-implement foreign context check * foreign context doesn't include the opening node itself * rewrite custom element checks to enforce the rule when possible * update custom tag tests * add custom tag test for children * replace custom tag check with regex + custom pattern option * add tests for custom pattern option * add test for preferred self closing custom tag with no children * Update require-closing-tags.md * add `mspace` to spellcheck https://developer.mozilla.org/en-US/docs/Web/MathML/Element/mspace * prettier * `customPattern` string -> `customPatterns` string array * format * lint * Update docs/rules/require-closing-tags.md Co-authored-by: YeonJuan <yeonjuan93@naver.com> * update test to expect removal of closing tag when fixing * remove closing tag in fixed output * update fixes * update tests to reflect new independent options spec * replace `allowSelfClosingCustom` + `customPatterns` with independent `selfClosingCustomPatterns` option and update foreign context handling to compensate * Update require-closing-tags.md * format * update default to disallow self-closing custom tags * update docs * format --------- Co-authored-by: YeonJuan <yeonjuan93@naver.com>
yeonjuan · Jun 8, 2024 · 9e968b9 · 9e968b9
1 parent c9095f0
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diff --git a/.cspell.json b/.cspell.json
@@ -31,6 +31,7 @@
     "noembed",
     "roletype",
     "nextid",
-    "screenreader"
+    "screenreader",
+    "mspace"
   ]
 }
diff --git a/docs/rules/require-closing-tags.md b/docs/rules/require-closing-tags.md
@@ -30,15 +30,15 @@ Examples of **correct** code for this rule:
 
 ### Options
 
-This rule has an object option for [Void Elements](https://html.spec.whatwg.org/multipage/syntax.html#void-elements).
+This rule has an object option for [Void Elements](https://html.spec.whatwg.org/multipage/syntax.html#void-elements) and custom element patterns.
 
 - `"selfClosing": "never"`: (default) disallow using self closing tag on [Void Elements](https://html.spec.whatwg.org/multipage/syntax.html#void-elements).
 
 - `"selfClosing": "always"`: enforce using self closing tag on [Void Elements](https://html.spec.whatwg.org/multipage/syntax.html#void-elements).
 
-- `"allowSelfClosingCustom": false`: (default) disallow self-closing for the custom tags.
+- `"selfClosingCustomPatterns": []`: (default) disallow self-closing for custom tags.
 
-- `"allowSelfClosingCustom": true`: allow self-closing for the custom tags.
+- `"selfClosingCustomPatterns": ["-"]`: enforce self-closing for tags matching any of an array of strings representing regular expression pattern (e.g. tags including `-` in the name).
 
 #### selfClosing : "never"
 
@@ -76,32 +76,37 @@ Examples of **correct** code for the `{ "selfClosing": "always" }` option:
 <base />
 ```
 
-#### "allowSelfClosingCustom": false
+#### selfClosingCustomPatterns: ["-"]
 
-Examples of **incorrect** code for the `{ "allowSelfClosingCustom": false }` option:
+Examples of **incorrect** code for the `{ "selfClosingCustomPatterns": ["-"] }` option:
 
 <!-- prettier-ignore -->
 ```html,incorrect
-<custom-tag />
+<custom-tag> </custom-tag>
 ```
 
-Examples of **correct** code for the `{ "allowSelfClosingCustom": false }` option:
+Examples of **correct** code for the `{ "selfClosingCustomPatterns": ["-"] }` option:
 
 <!-- prettier-ignore -->
 ```html,correct
-<custom-tag> </custom-tag>
+<custom-tag>children</custom-tag>
+<custom-tag />
 ```
 
-#### "allowSelfClosingCustom": true
+#### selfClosingCustomPatterns: []
 
-Examples of **correct** code for the `{ "allowSelfClosingCustom": true }` option:
+Examples of **incorrect** code for the `{ "allowSelfClosingCustom": [] }` option:
 
 <!-- prettier-ignore -->
-```html,correct
-<!-- both allowed -->
+```html,incorrect
+<custom-tag />
+```
+
+Examples of **correct** code for the `{ "allowSelfClosingCustom": [] }` option:
 
+<!-- prettier-ignore -->
+```html,correct
 <custom-tag> </custom-tag>
-<custom-tag />
 ```
 
 ## Further Reading

diff --git a/packages/eslint-plugin/lib/rules/require-closing-tags.js b/packages/eslint-plugin/lib/rules/require-closing-tags.js
@@ -34,8 +34,11 @@ module.exports = {
           selfClosing: {
             enum: ["always", "never"],
           },
-          allowSelfClosingCustom: {
-            type: "boolean",
+          selfClosingCustomPatterns: {
+            type: "array",
+            items: {
+              type: "string",
+            },
           },
         },
         additionalProperties: false,
@@ -49,14 +52,21 @@ module.exports = {
   },
 
   create(context) {
-    const shouldSelfClose =
+    /** @type {string[]} */
+    const foreignContext = [];
+    const shouldSelfCloseVoid =
       context.options && context.options.length
         ? context.options[0].selfClosing === "always"
         : false;
-    const allowSelfClosingCustom =
-      context.options && context.options.length
-        ? context.options[0].allowSelfClosingCustom === true
-        : false;
+    /** @type {string[]} */
+    const selfClosingCustomPatternsOption =
+      (context.options &&
+        context.options.length &&
+        context.options[0].selfClosingCustomPatterns) ||
+      [];
+    const selfClosingCustomPatterns = selfClosingCustomPatternsOption.map(
+      (i) => new RegExp(i)
+    );
 
     /**
      * @param {TagNode} node
@@ -91,7 +101,10 @@ module.exports = {
             if (!fixable) {
               return null;
             }
-            return fixer.replaceText(node.openEnd, " />");
+            const fixes = [];
+            fixes.push(fixer.replaceText(node.openEnd, " />"));
+            if (node.close) fixes.push(fixer.remove(node.close));
+            return fixes;
           },
         });
       }
@@ -115,17 +128,33 @@ module.exports = {
     return {
       Tag(node) {
         const isVoidElement = VOID_ELEMENTS_SET.has(node.name);
-        if (
-          node.selfClosing &&
-          allowSelfClosingCustom &&
-          node.name.indexOf("-") !== -1
-        ) {
-          checkVoidElement(node, true, false);
-        } else if (node.selfClosing || isVoidElement) {
-          checkVoidElement(node, shouldSelfClose, isVoidElement);
+        const isSelfClosingCustomElement = !!selfClosingCustomPatterns.some(
+          (i) => node.name.match(i)
+        );
+        const isForeign = foreignContext.length > 0;
+        const shouldSelfCloseCustom =
+          isSelfClosingCustomElement && !node.children.length;
+        const shouldSelfCloseForeign = node.selfClosing;
+        const shouldSelfClose =
+          (isVoidElement && shouldSelfCloseVoid) ||
+          (isSelfClosingCustomElement && shouldSelfCloseCustom) ||
+          (isForeign && shouldSelfCloseForeign);
+        const canSelfClose =
+          isVoidElement || isSelfClosingCustomElement || isForeign;
+        if (node.selfClosing || canSelfClose) {
+          checkVoidElement(node, shouldSelfClose, canSelfClose);
         } else if (node.openEnd.value !== "/>") {
           checkClosingTag(node);
         }
+        if (["svg", "math"].includes(node.name)) foreignContext.push(node.name);
+      },
+      /**
+       * @param {TagNode} node
+       */
+      "Tag:exit"(node) {
+        if (node.name === foreignContext[foreignContext.length - 1]) {
+          foreignContext.pop();
+        }
       },
     };
   },

diff --git a/packages/eslint-plugin/tests/rules/require-closing-tags.test.js b/packages/eslint-plugin/tests/rules/require-closing-tags.test.js
@@ -23,39 +23,47 @@ ruleTester.run("require-closing-tags", rule, {
       code: `<custom-tag> </custom-tag>`,
       options: [
         {
-          allowSelfClosingCustom: false,
+          selfClosingCustomPatterns: [],
         },
       ],
     },
     {
       code: `<custom-tag/>`,
       options: [
         {
-          allowSelfClosingCustom: true,
+          selfClosingCustomPatterns: ["-"],
         },
       ],
     },
     {
       code: `<custom-tag />`,
       options: [
         {
-          allowSelfClosingCustom: true,
+          selfClosingCustomPatterns: ["-"],
         },
       ],
     },
     {
       code: `<custom-tag> </custom-tag>`,
       options: [
         {
-          allowSelfClosingCustom: true,
+          selfClosingCustomPatterns: ["-"],
         },
       ],
     },
     {
       code: `<custom-tag id="foo" />`,
       options: [
         {
-          allowSelfClosingCustom: true,
+          selfClosingCustomPatterns: ["-"],
+        },
+      ],
+    },
+    {
+      code: `<custom-tag>children</custom-tag>`,
+      options: [
+        {
+          selfClosingCustomPatterns: ["-"],
         },
       ],
     },
@@ -75,6 +83,20 @@ ruleTester.run("require-closing-tags", rule, {
 		  <circle />
 </svg>
     </body>
+`,
+      options: [
+        {
+          selfClosing: "always",
+        },
+      ],
+    },
+    {
+      code: `
+    <body>
+      <math>
+        1<mspace width="100px" />2
+      </math>
+    </body>
 `,
       options: [
         {
@@ -142,7 +164,7 @@ ruleTester.run("require-closing-tags", rule, {
       code: `<custom-tag />`,
       options: [
         {
-          allowSelfClosingCustom: false,
+          selfClosingCustomPatterns: [],
         },
       ],
       errors: [
@@ -155,7 +177,34 @@ ruleTester.run("require-closing-tags", rule, {
       code: `<custom-tag id="foo" />`,
       options: [
         {
-          allowSelfClosingCustom: false,
+          selfClosingCustomPatterns: [],
+        },
+      ],
+      errors: [
+        {
+          messageId: "unexpected",
+        },
+      ],
+    },
+    {
+      code: `<custom-tag></custom-tag>`,
+      options: [
+        {
+          selfClosingCustomPatterns: ["-"],
+        },
+      ],
+      output: "<custom-tag />",
+      errors: [
+        {
+          messageId: "missingSelf",
+        },
+      ],
+    },
+    {
+      code: `<div />`,
+      options: [
+        {
+          selfClosing: "always",
         },
       ],
       output: null,