Extract rule: template-require-form-method

Author: NullVoxPopuli

README.md

@@ -244,6 +244,7 @@ rules in templates can be disabled with eslint directives with mustache or html
 | [template-no-obsolete-elements](docs/rules/template-no-obsolete-elements.md)                                 | disallow obsolete HTML elements                                              |    |    |    |
 | [template-no-outlet-outside-routes](docs/rules/template-no-outlet-outside-routes.md)                         | disallow {{outlet}} outside of route templates                               |    |    |    |
 | [template-no-page-title-component](docs/rules/template-no-page-title-component.md)                           | disallow usage of ember-page-title component                                 |    |    |    |
+| [template-require-form-method](docs/rules/template-require-form-method.md)                                   | require form method attribute                                                |    |    |    |
 
 ### Components
 

docs/rules/template-require-form-method.md

@@ -0,0 +1,71 @@
+# ember/template-require-form-method
+
+<!-- end auto-generated rule header -->
+
+Require form elements to have a method attribute.
+
+Form elements should explicitly specify the HTTP method they use. This improves code clarity and helps catch potential issues.
+
+## Examples
+
+This rule **forbids** the following:
+
+```gjs
+<template>
+  <form></form>
+</template>
+```
+
+```gjs
+<template>
+  <form method='DELETE'></form>
+</template>
+```
+
+This rule **allows** the following:
+
+```gjs
+<template>
+  <form method='POST'></form>
+</template>
+```
+
+```gjs
+<template>
+  <form method='GET'></form>
+</template>
+```
+
+```gjs
+<template>
+  <form method='DIALOG'></form>
+</template>
+```
+
+```gjs
+<template>
+  <form method='{{dynamicMethod}}'></form>
+</template>
+```
+
+## Configuration
+
+- `allowedMethods` (default: `['POST', 'GET', 'DIALOG']`) - Array of allowed form method values
+
+```js
+// .eslintrc.js
+module.exports = {
+  rules: {
+    'ember/template-require-form-method': [
+      'error',
+      {
+        allowedMethods: ['POST', 'GET'],
+      },
+    ],
+  },
+};
+```
+
+## References
+
+- [HTML Spec - Form Method Attribute](https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fs-method)

lib/rules/template-require-form-method.js

@@ -0,0 +1,115 @@
+// Form `method` attribute keywords:
+// https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fs-method
+const VALID_FORM_METHODS = ['POST', 'GET', 'DIALOG'];
+
+const DEFAULT_CONFIG = {
+  allowedMethods: VALID_FORM_METHODS,
+};
+
+function parseConfig(config) {
+  if (config === false || config === undefined) {
+    return false;
+  }
+
+  if (config === true) {
+    return DEFAULT_CONFIG;
+  }
+
+  if (typeof config === 'object' && Array.isArray(config.allowedMethods)) {
+    const allowedMethods = config.allowedMethods.map((m) => String(m).toUpperCase());
+
+    // Check if all methods are valid
+    const hasAllValid = allowedMethods.every((m) => VALID_FORM_METHODS.includes(m));
+
+    if (hasAllValid) {
+      return { allowedMethods };
+    }
+  }
+
+  return false;
+}
+
+function makeErrorMessage(methods) {
+  return `All \`<form>\` elements should have \`method\` attribute with value of \`${methods.join(',')}\``;
+}
+
+/** @type {import('eslint').Rule.RuleModule} */
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'require form method attribute',
+      category: 'Best Practices',
+      recommended: false,
+      url: 'https://github.com/ember-cli/eslint-plugin-ember/tree/master/docs/rules/template-require-form-method.md',
+      templateMode: 'both',
+    },
+    fixable: null,
+    schema: [
+      {
+        oneOf: [
+          {
+            type: 'object',
+            properties: {
+              allowedMethods: {
+                type: 'array',
+                items: {
+                  type: 'string',
+                },
+              },
+            },
+            additionalProperties: false,
+          },
+        ],
+      },
+    ],
+    messages: {},
+    originallyFrom: {
+      name: 'ember-template-lint',
+      rule: 'lib/rules/require-form-method.js',
+      docs: 'docs/rule/require-form-method.md',
+      tests: 'test/unit/rules/require-form-method-test.js',
+    },
+  },
+
+  create(context) {
+    // If no options provided, use defaults
+    let config = context.options[0];
+    config = config ? parseConfig(config) : DEFAULT_CONFIG;
+
+    if (config === false) {
+      return {};
+    }
+
+    return {
+      GlimmerElementNode(node) {
+        if (node.tag !== 'form') {
+          return;
+        }
+
+        const methodAttribute = node.attributes.find((attr) => attr.name === 'method');
+
+        if (!methodAttribute) {
+          context.report({
+            node,
+            message: makeErrorMessage(config.allowedMethods),
+          });
+          return;
+        }
+
+        // Check if it's a text value
+        if (methodAttribute.value && methodAttribute.value.type === 'GlimmerTextNode') {
+          const methodValue = methodAttribute.value.chars.toUpperCase();
+
+          if (!config.allowedMethods.includes(methodValue)) {
+            context.report({
+              node,
+              message: makeErrorMessage(config.allowedMethods),
+            });
+          }
+        }
+        // If it's a dynamic value (like {{foo}}), don't report
+      },
+    };
+  },
+};