angular-app-monaco-editor-integration/monaco-editor/monaco-editor-config.ts

async function onMonacoEditorLoad(languages: Array<string> = ['java', 'csharp', 'python', 'html', 'json', 'css']) {
  const allLangs =  (<any>window).monaco.languages.getLanguages();
  console.log('all supported languages:', allLangs);
  console.log( (<any>window).monaco);
  (<any>window).monaco.languages.register({ id: languages[0] });
  (<any>window).monaco.languages.registerCompletionItemProvider(languages[0], {
    triggerCharacters: ['.'],
    provideCompletionItems: function (model: any, position: any) {
      const textUntilPosition = model.getValueInRange(
        {
          startLineNumber: position.lineNumber, 
          startColumn: 1,
          endLineNumber: position.lineNumber,
          endColumn: position.column
        }
      );
      console.log(textUntilPosition);
      const match = textUntilPosition.match(/"dependencies"\s*:\s*\{\s*("[^"]*"\s*:\s*"[^"]*"\s*,\s*)*([^"]*)?$/);
      if (!match) {
        return { suggestions: [] };
      }
      var word = model.getWordUntilPosition(position);
      var range = {
        startLineNumber: position.lineNumber,
        endLineNumber: position.lineNumber,
        startColumn: word.startColumn,
        endColumn: word.endColumn
      };

      const suggestions = [
        {
          label: '"lodash"',
          kind:  (<any>window).monaco.languages.CompletionItemKind.Function,
          documentation: "The Lodash library exported as Node.js modules.",
          insertText: '"lodash": "*"',
          range: range
        },
        {
          label: '"express"',
          kind:  (<any>window).monaco.languages.CompletionItemKind.Function,
          documentation: "Fast, unopinionated, minimalist web framework",
          insertText: '"express": "*"',
          range: range
        },
        {
          label: '"mkdirp"',
          kind:  (<any>window).monaco.languages.CompletionItemKind.Function,
          documentation: "Recursively mkdir, like <code>mkdir -p</code>",
          insertText: '"mkdirp": "*"',
          range: range
        },
        {
          label: '"my-third-party-library"',
          kind:  (<any>window).monaco.languages.CompletionItemKind.Function,
          documentation: "Describe your library here",
          insertText: '"${1:my-third-party-library}": "${2:1.2.3}"',
          insertTextRules:  (<any>window).monaco.languages.CompletionItemInsertTextRule.InsertAsSnippet,
          range: range
        }
      ];
      return { suggestions: suggestions };
    }

  });
}

export const monacoConfig = {
  baseUrl: './assets',
  defaultOptions: { scrollBeyondLastLine: false },
  onMonacoLoad: onMonacoEditorLoad
};