feat(require-template): add rule; fixes part of gajus#1120

.README/rules/require-template.md

@@ -0,0 +1,54 @@
+# `require-template`
+
+Checks to see that `@template` tags are present for any detected type
+parameters.
+
+Currently checks `TSTypeAliasDeclaration` such as:
+
+```ts
+export type Pairs<D, V> = [D, V | undefined];
+```
+
+or
+
+```js
+/**
+ * @typedef {[D, V | undefined]} Pairs
+ */
+```
+
+Note that in the latter TypeScript-flavor JavaScript example, there is no way
+for us to firmly distinguish between `D` and `V` as type parameters or as some
+other identifiers, so we use an algorithm that any single capital letters
+are assumed to be templates.
+
+## Options
+
+### `requireSeparateTemplates`
+
+Requires that each template have its own separate line, i.e., preventing
+templates of this format:
+
+```js
+/**
+ * @template T, U, V
+ */
+```
+
+Defaults to `false`.
+
+|||
+|---|---|
+|Context|everywhere|
+|Tags|`template`|
+|Recommended|true|
+|Settings||
+|Options|`requireSeparateTemplates`|
+
+## Failing examples
+
+<!-- assertions-failing requireTemplate -->
+
+## Passing examples
+
+<!-- assertions-passing requireTemplate -->

.ncurc.cjs

@@ -2,7 +2,7 @@
 
 module.exports = {
   reject: [
-    // Todo: When package converted to ESM only
+    // Todo: When our package converted to ESM only
     'escape-string-regexp',
 
     // todo[engine:node@>=20]: Can reenable

docs/rules/require-template.md

@@ -0,0 +1,147 @@
+<a name="user-content-require-template"></a>
+<a name="require-template"></a>
+# <code>require-template</code>
+
+Checks to see that `@template` tags are present for any detected type
+parameters.
+
+Currently checks `TSTypeAliasDeclaration` such as:
+
+```ts
+export type Pairs<D, V> = [D, V | undefined];
+```
+
+or
+
+```js
+/**
+ * @typedef {[D, V | undefined]} Pairs
+ */
+```
+
+Note that in the latter TypeScript-flavor JavaScript example, there is no way
+for us to firmly distinguish between `D` and `V` as type parameters or as some
+other identifiers, so we use an algorithm that any single capital letters
+are assumed to be templates.
+
+<a name="user-content-require-template-options"></a>
+<a name="require-template-options"></a>
+## Options
+
+<a name="user-content-require-template-options-requireseparatetemplates"></a>
+<a name="require-template-options-requireseparatetemplates"></a>
+### <code>requireSeparateTemplates</code>
+
+Requires that each template have its own separate line, i.e., preventing
+templates of this format:
+
+```js
+/**
+ * @template T, U, V
+ */
+```
+
+Defaults to `false`.
+
+|||
+|---|---|
+|Context|everywhere|
+|Tags|`template`|
+|Recommended|true|
+|Settings||
+|Options|`requireSeparateTemplates`|
+
+<a name="user-content-require-template-failing-examples"></a>
+<a name="require-template-failing-examples"></a>
+## Failing examples
+
+The following patterns are considered problems:
+
+````js
+/**
+ *
+ */
+type Pairs<D, V> = [D, V | undefined];
+// Message: Missing @template D
+
+/**
+ *
+ */
+export type Pairs<D, V> = [D, V | undefined];
+// Message: Missing @template D
+
+/**
+ * @typedef {[D, V | undefined]} Pairs
+ */
+// Message: Missing @template D
+
+/**
+ * @typedef {[D, V | undefined]} Pairs
+ */
+// Settings: {"jsdoc":{"mode":"permissive"}}
+// Message: Missing @template D
+
+/**
+ * @template D, U
+ */
+export type Extras<D, U, V> = [D, U, V | undefined];
+// Message: Missing @template V
+
+/**
+ * @template D, U
+ * @typedef {[D, U, V | undefined]} Extras
+ */
+// Message: Missing @template V
+
+/**
+ * @template D, V
+ */
+export type Pairs<D, V> = [D, V | undefined];
+// "jsdoc/require-template": ["error"|"warn", {"requireSeparateTemplates":true}]
+// Message: Missing separate @template for V
+
+/**
+ * @template D, V
+ * @typedef {[D, V | undefined]} Pairs
+ */
+// "jsdoc/require-template": ["error"|"warn", {"requireSeparateTemplates":true}]
+// Message: Missing separate @template for V
+````
+
+
+
+<a name="user-content-require-template-passing-examples"></a>
+<a name="require-template-passing-examples"></a>
+## Passing examples
+
+The following patterns are not considered problems:
+
+````js
+/**
+ * @template D
+ * @template V
+ */
+export type Pairs<D, V> = [D, V | undefined];
+
+/**
+ * @template D
+ * @template V
+ * @typedef {[D, V | undefined]} Pairs
+ */
+
+/**
+ * @template D, U, V
+ */
+export type Extras<D, U, V> = [D, U, V | undefined];
+
+/**
+ * @template D, U, V
+ * @typedef {[D, U, V | undefined]} Extras
+ */
+
+/**
+ * @typedef {[D, U, V | undefined]} Extras
+ * @typedef {[D, U, V | undefined]} Extras
+ */
+````
+

src/index.js

@@ -45,6 +45,7 @@ import requireReturns from './rules/requireReturns.js';
 import requireReturnsCheck from './rules/requireReturnsCheck.js';
 import requireReturnsDescription from './rules/requireReturnsDescription.js';
 import requireReturnsType from './rules/requireReturnsType.js';
+import requireTemplate from './rules/requireTemplate.js';
 import requireThrows from './rules/requireThrows.js';
 import requireYields from './rules/requireYields.js';
 import requireYieldsCheck from './rules/requireYieldsCheck.js';
@@ -118,6 +119,7 @@ const index = {
     'require-returns-check': requireReturnsCheck,
     'require-returns-description': requireReturnsDescription,
     'require-returns-type': requireReturnsType,
+    'require-template': requireTemplate,
     'require-throws': requireThrows,
     'require-yields': requireYields,
     'require-yields-check': requireYieldsCheck,
@@ -191,6 +193,7 @@ const createRecommendedRuleset = (warnOrError, flatName) => {
       'jsdoc/require-returns-check': warnOrError,
       'jsdoc/require-returns-description': warnOrError,
       'jsdoc/require-returns-type': warnOrError,
+      'jsdoc/require-template': warnOrError,
       'jsdoc/require-throws': 'off',
       'jsdoc/require-yields': warnOrError,
       'jsdoc/require-yields-check': warnOrError,

src/rules/requireTemplate.js

@@ -0,0 +1,119 @@
+import {
+  parse as parseType,
+  traverse,
+  tryParse as tryParseType,
+} from '@es-joy/jsdoccomment';
+import iterateJsdoc from '../iterateJsdoc.js';
+
+export default iterateJsdoc(({
+  context,
+  utils,
+  node,
+  settings,
+  report,
+}) => {
+  const {
+    requireSeparateTemplates = false,
+  } = context.options[0] || {};
+
+  const {
+    mode
+  } = settings;
+
+  const usedNames = new Set();
+  const templateTags = utils.getTags('template');
+  const templateNames = templateTags.flatMap(({name}) => {
+    return name.split(/,\s*/);
+  });
+
+  for (const tag of templateTags) {
+    const {name} = tag;
+    const names = name.split(/,\s*/);
+    if (requireSeparateTemplates && names.length > 1) {
+      report(`Missing separate @template for ${names[1]}`, null, tag);
+    }
+  }
+
+  /**
+   * @param {import('@typescript-eslint/types').TSESTree.TSTypeAliasDeclaration} aliasDeclaration
+   */
+  const checkParameters = (aliasDeclaration) => {
+    /* c8 ignore next -- Guard */
+    const {params} = aliasDeclaration.typeParameters ?? {params: []};
+    for (const {name: {name}} of params) {
+      usedNames.add(name);
+    }
+    for (const usedName of usedNames) {
+      if (!templateNames.includes(usedName)) {
+        report(`Missing @template ${usedName}`);
+      }
+    }
+  };
+
+  const handleTypeAliases = () => {
+    const nde = /** @type {import('@typescript-eslint/types').TSESTree.Node} */ (
+      node
+    );
+    if (!nde) {
+      return;
+    }
+    switch (nde.type) {
+    case 'ExportNamedDeclaration':
+      if (nde.declaration?.type === 'TSTypeAliasDeclaration') {
+        checkParameters(nde.declaration);
+      }
+      break;
+    case 'TSTypeAliasDeclaration':
+      checkParameters(nde);
+      break;
+    }
+  };
+
+  const typedefTags = utils.getTags('typedef');
+  if (!typedefTags.length || typedefTags.length >= 2) {
+    handleTypeAliases();
+    return;
+  }
+
+  const potentialType = typedefTags[0].type;
+  const parsedType = mode === 'permissive' ?
+    tryParseType(/** @type {string} */ (potentialType)) :
+    parseType(/** @type {string} */ (potentialType), mode)
+
+  traverse(parsedType, (nde) => {
+    const {
+      type,
+      value,
+    } = /** @type {import('jsdoc-type-pratt-parser').NameResult} */ (nde);
+    if (type === 'JsdocTypeName' && (/^[A-Z]$/).test(value)) {
+      usedNames.add(value);
+    }
+  });
+
+  // Could check against whitelist/blacklist
+  for (const usedName of usedNames) {
+    if (!templateNames.includes(usedName)) {
+      report(`Missing @template ${usedName}`, null, typedefTags[0]);
+    }
+  }
+}, {
+  iterateAllJsdocs: true,
+  meta: {
+    docs: {
+      description: 'Requires template tags for each generic type parameter',
+      url: 'https://github.com/gajus/eslint-plugin-jsdoc/blob/main/docs/rules/require-template.md#repos-sticky-header',
+    },
+    schema: [
+      {
+        additionalProperties: false,
+        properties: {
+          requireSeparateTemplates: {
+            type: 'boolean'
+          }
+        },
+        type: 'object',
+      },
+    ],
+    type: 'suggestion',
+  },
+});