eslint-plugin-jsdoc/src/rules/requireTemplate.js

JSDoc linting rules for ESLint.

import iterateJsdoc from '../iterateJsdoc.js';
import {
  parse as parseType,
  traverse,
  tryParse as tryParseType,
} from '@es-joy/jsdoccomment';

export default iterateJsdoc(({
  context,
  node,
  report,
  settings,
  utils,
}) => {
  if (utils.avoidDocs()) {
    return;
  }

  const {
    requireSeparateTemplates = false,
  } = context.options[0] || {};

  const {
    mode,
  } = settings;

  const usedNames = new Set();
  const templateTags = utils.getTags('template');
  const templateNames = templateTags.flatMap((tag) => {
    return utils.parseClosureTemplateTag(tag);
  });

  if (requireSeparateTemplates) {
    for (const tag of templateTags) {
      const names = utils.parseClosureTemplateTag(tag);
      if (names.length > 1) {
        report(`Missing separate @template for ${names[1]}`, null, tag);
      }
    }
  }

  /**
   * @param {import('@typescript-eslint/types').TSESTree.FunctionDeclaration|
   *   import('@typescript-eslint/types').TSESTree.ClassDeclaration|
   *   import('@typescript-eslint/types').TSESTree.TSDeclareFunction|
   *   import('@typescript-eslint/types').TSESTree.TSInterfaceDeclaration|
   *   import('@typescript-eslint/types').TSESTree.TSTypeAliasDeclaration} aliasDeclaration
   */
  const checkTypeParams = (aliasDeclaration) => {
    const {
      params,
      /* c8 ignore next -- Guard */
    } = aliasDeclaration.typeParameters ?? {
      /* c8 ignore next -- Guard */
      params: [],
    };
    for (const {
      name: {
        name,
      },
    } of params) {
      usedNames.add(name);
    }

    for (const usedName of usedNames) {
      if (!templateNames.includes(usedName)) {
        report(`Missing @template ${usedName}`);
      }
    }
  };

  const handleTypes = () => {
    const nde = /** @type {import('@typescript-eslint/types').TSESTree.Node} */ (
      node
    );
    if (!nde) {
      return;
    }

    switch (nde.type) {
      case 'ClassDeclaration':
      case 'FunctionDeclaration':
      case 'TSDeclareFunction':
      case 'TSInterfaceDeclaration':
      case 'TSTypeAliasDeclaration':
        checkTypeParams(nde);
        break;
      case 'ExportDefaultDeclaration':
        switch (nde.declaration?.type) {
          case 'ClassDeclaration':
          case 'FunctionDeclaration':
          case 'TSInterfaceDeclaration':
            checkTypeParams(nde.declaration);
            break;
        }

        break;
      case 'ExportNamedDeclaration':
        switch (nde.declaration?.type) {
          case 'ClassDeclaration':
          case 'FunctionDeclaration':
          case 'TSDeclareFunction':
          case 'TSInterfaceDeclaration':
          case 'TSTypeAliasDeclaration':
            checkTypeParams(nde.declaration);
            break;
        }

        break;
    }
  };

  const usedNameToTag = new Map();

  /**
   * @param {import('comment-parser').Spec} potentialTag
   */
  const checkForUsedTypes = (potentialTag) => {
    let parsedType;
    try {
      parsedType = mode === 'permissive' ?
        tryParseType(/** @type {string} */ (potentialTag.type)) :
        parseType(/** @type {string} */ (potentialTag.type), mode);
    } catch {
      return;
    }

    traverse(parsedType, (nde) => {
      const {
        type,
        value,
      } = /** @type {import('jsdoc-type-pratt-parser').NameResult} */ (nde);
      if (type === 'JsdocTypeName' && (/^[A-Z]$/v).test(value)) {
        usedNames.add(value);
        if (!usedNameToTag.has(value)) {
          usedNameToTag.set(value, potentialTag);
        }
      }
    });
  };

  /**
   * @param {string[]} tagNames
   */
  const checkTagsAndTemplates = (tagNames) => {
    for (const tagName of tagNames) {
      const preferredTagName = /** @type {string} */ (utils.getPreferredTagName({
        tagName,
      }));
      const matchingTags = utils.getTags(preferredTagName);
      for (const matchingTag of matchingTags) {
        checkForUsedTypes(matchingTag);
      }
    }

    // Could check against whitelist/blacklist
    for (const usedName of usedNames) {
      if (!templateNames.includes(usedName)) {
        report(`Missing @template ${usedName}`, null, usedNameToTag.get(usedName));
      }
    }
  };

  const callbackTags = utils.getTags('callback');
  const functionTags = utils.getTags('function');
  if (callbackTags.length || functionTags.length) {
    checkTagsAndTemplates([
      'param', 'returns',
    ]);
    return;
  }

  const typedefTags = utils.getTags('typedef');
  if (!typedefTags.length || typedefTags.length >= 2) {
    handleTypes();
    return;
  }

  const potentialTypedef = typedefTags[0];
  checkForUsedTypes(potentialTypedef);

  checkTagsAndTemplates([
    'property',
  ]);
}, {
  iterateAllJsdocs: true,
  meta: {
    docs: {
      description: 'Requires `@template` tags be present when type parameters are used.',
      url: 'https://github.com/gajus/eslint-plugin-jsdoc/blob/main/docs/rules/require-template.md#repos-sticky-header',
    },
    schema: [
      {
        additionalProperties: false,
        properties: {
          exemptedBy: {
            description: `Array of tags (e.g., \`['type']\`) whose presence on the document
block avoids the need for a \`@template\`. Defaults to an array with
\`inheritdoc\`. If you set this array, it will overwrite the default,
so be sure to add back \`inheritdoc\` if you wish its presence to cause
exemption of the rule.`,
            items: {
              type: 'string',
            },
            type: 'array',
          },
          requireSeparateTemplates: {
            description: `Requires that each template have its own separate line, i.e., preventing
templates of this format:

\`\`\`js
/**
 * @template T, U, V
 */
\`\`\`

Defaults to \`false\`.`,
            type: 'boolean',
          },
        },
        type: 'object',
      },
    ],
    type: 'suggestion',
  },
});