Show errors on typo/random characters for js

I’m using Codemirror v6 and I need to show errors in editor when user make a typo or enters random characters like this:

I didn’t find anything like that in documentation. Is there any way to do that?

I think you might be referring to linting. The library comes with an extension that you can wire up to external linters, but does not ship with its own JavaScript linter. If you manage to run ESLint in the browser (which is unfortunately huge and not written for browser environments), you could use this shim to use it in the editor.

I’m using Linter from ‘eslint-linter-browserify’ because it supports top level await and latest parserOptions.ecmaVersion. But I don’t understand what I should do so that this linter understands typos and “asdfasdf” text in code.
My extensions configuration looks like this:

const extensions = [
      linter(esLint(new Linter(), {
        noInlineConfig: true,
        extends: ['strict', 'strict/browser'],
        parserOptions: {
          ecmaVersion: 'latest',
          sourceType: 'module',
        },
        env: {
          browser: true,
        },
        rules: {
          'no-restricted-imports': ['error'],
          'no-eval': ['error'],
          'no-unused-vars': ['error'],
          'no-restricted-globals': [
            'error',
            'window',
            'document',
            'Event',
            'Function',
            'AbortController',
            'AbortSignal',
            'AbstractRange',
            'Attr',
            'CDATASection',
            'CharacterData',
            'Comment',
            'CustomEvent',
            'Document',
            'DocumentFragment',
            'DocumentType',
            'DOMError',
            'DOMException',
            'DOMImplementation',
            'DOMParser',
            'DOMPoint',
            'DOMPointReadOnly',
            'DOMRect',
            'DOMTokenList',
            'Element',
            'Event',
            'EventTarget',
            'HTMLCollection',
            'MutationObserver',
            'MutationRecord',
            'NamedNodeMap',
            'Node',
            'NodeIterator',
            'NodeList',
            'ProcessingInstruction',
            'Range',
            'StaticRange',
            'Text',
            'TextDecoder',
            'TextEncoder',
            'TimeRanges',
            'TreeWalker',
            'XMLDocument',
          ],
          'no-alert': ['error'],
        },
      })),
      lintGutter(),
      basicSetup,
      javascript(),
    ];