TypeError: Cannot read property 'body' of null

Tell us about your environment

• ESLint Version: 7.8.1
• Node Version: 12.14.1
• npm Version: 6.14.5

What parser (default, @babel/eslint-parser, @typescript-eslint/parser, etc.) are you using? @typescript-eslint/parser

Please show your full configuration:

Configuration

module.exports = {
  root: true,

  env: {
    node: true,
    browser: true
  },

  extends: [
    'plugin:vue/strongly-recommended',
    '@vue/airbnb',
    '@vue/typescript',
    'plugin:prettier/recommended',
    'prettier',
    'prettier/@typescript-eslint',
    'prettier/vue'
  ],

  parserOptions: {
    ecmaVersion: 2020,
    parser: '@typescript-eslint/parser',
    sourceType: 'module'
  },

  rules: {
    'no-console': 'off',
    'no-debugger': 'off',
    '@typescript-eslint/no-empty-function': 'off',
    '@typescript-eslint/no-namespace': 'off',
    '@typescript-eslint/no-explicit-any': 'off',
    '@typescript-eslint/no-non-null-assertion': 'off',
    '@typescript-eslint/no-non-null-asserted-optional-chain': 'off',
    'class-methods-use-this': 'off',
    'vue/component-name-in-template-casing': ['error', 'PascalCase'],
    'vue/no-v-html': 'off',
    'no-shadow': 'off',
    'vue/max-attributes-per-line': [
      2,
      {
        singleline: 20,
        multiline: {
          max: 1,
          allowFirstLine: false
        }
      }
    ],
    'prettier/prettier': 'warn'
  },

  overrides: [
    {
      files: ['**/*.test.ts'],
      env: {
        jest: true
      }
    }
  ]
};

What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.

tiptap-extensions.d.ts

declare module 'tiptap-extensions' {
  import { Extension, Node, Mark } from 'tiptap';
  import { Node as PromsemirrorNode } from 'prosemirror-model';

  export interface PlaceholderOptions {
    emptyNodeClass?: string;
    emptyNodeText?: ((node: PromsemirrorNode) => string | undefined) | string;
    showOnlyWhenEditable?: boolean;
    showOnlyCurrent?: boolean;
    emptyEditorClass: string;
  }
  export class Placeholder extends Extension {
    constructor(options?: PlaceholderOptions);
  }

  export interface TrailingNodeOptions {
    /**
     * Node to be at the end of the document
     *
     * defaults to 'paragraph'
     */
    node: string;
    /**
     * The trailing node will not be displayed after these specified nodes.
     */
    notAfter: string[];
  }
  export class TrailingNode extends Extension {
    constructor(options?: TrailingNodeOptions);
  }

  export interface HeadingOptions {
    levels?: number[];
  }

  export class History extends Extension {}

  export class Bold extends Mark {}
  export class Code extends Mark {}
  export class Italic extends Mark {}
  export class Link extends Mark {}
  export class Strike extends Mark {}
  export class Underline extends Mark {}

  export class Blockquote extends Node {}
  export class BulletList extends Node {}
  export class CodeBlock extends Node {}
  export class HardBreak extends Node {}
  export class Heading extends Node {
    constructor(options?: HeadingOptions);
  }
  export class HorizontalRule extends Node {}
  export class Image extends Node {}
  export class ListItem extends Node {}
  export class OrderedList extends Node {}
  export class Table extends Node {}
  export class TableCell extends Node {}
  export class TableRow extends Node {}
  export class TableHeader extends Node {}
  export class TodoItem extends Node {}
  export class TodoList extends Node {}
}

vue-cli-service lint

What did you expect to happen? I expect eslint to tell me there is an error with the file or not without crashing

What actually happened? Please include the actual, raw output from ESLint. ERROR TypeError: Cannot read property ‘body’ of null Occurred while linting \SkyCourt.UI\ui\src\typings\tiptap-extensions.d.ts:13 TypeError: Cannot read property ‘body’ of null Occurred while linting SkyCourt.UI\ui\src\typings\tiptap-extensions.d.ts:13 at checkForConstructor (SkyCourt.UI\ui\node_modules\eslint\lib\rules\no-useless-constructor.js:165:42) at SkyCourt.UI\ui\node_modules\eslint\lib\linter\safe-emitter.js:45:58 at Array.forEach (<anonymous>) at Object.emit (SkyCourt.UI\ui\node_modules\eslint\lib\linter\safe-emitter.js:45:38) at NodeEventGenerator.applySelector (SkyCourt.UI\ui\node_modules\eslint\lib\linter\node-event-generator.js:254:26) at NodeEventGenerator.applySelectors (SkyCourt.UI\ui\node_modules\eslint\lib\linter\node-event-generator.js:283:22) at CodePathAnalyzer.enterNode (SkyCourt.UI\ui\node_modules\eslint\lib\linter\code-path-analysis\code-path-analyzer.js:711:23) at SkyCourt.UI\ui\node_modules\eslint\lib\linter\linter.js:952:32 at Array.forEach (<anonymous>) at runRules (SkyCourt.UI\ui\node_modules\eslint\lib\linter\linter.js:947:15) at Linter._verifyWithoutProcessors (SkyCourt.UI\ui\node_modules\eslint\lib\linter\linter.js:1173:31) at Linter._verifyWithConfigArray (SkyCourt.UI\ui\node_modules\eslint\lib\linter\linter.js:1271:21) at Linter.verify (SkyCourt.UI\ui\node_modules\eslint\lib\linter\linter.js:1226:25) at Linter.verifyAndFix (SkyCourt.UI\ui\node_modules\eslint\lib\linter\linter.js:1416:29) at verifyText (SkyCourt.UI\ui\node_modules\eslint\lib\cli-engine\cli-engine.js:224:48) error Command failed with exit code 1.

Are you willing to submit a pull request to fix this bug? I don’t presume to understand the eslint code enough to be able to provide a fix.

[gregveres]

Yea, that makes sense. I had mistakenly assumed that if somebody was suggesting a config (ie a set of extend packages) that it would have worked out all those kinks and favoured the extension rules. I was wrong, but I am on the right path now. I know what to look for in the future and I have started a set of overrides for .d.ts files in my config.

Thanks again for such a quick response!

[nzakas]

Looks like this is resolved, so closing.