javascript - Using CodeMirror. "Cannot set property 'modeOption' of undefined" - Stack Overflo

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Currently running into an issue with this.

const configDataNode = document.getElementById('config_data');
    const editor = CodeMirror.fromTextArea(
      document.getElementById('config_data_editor'),
      {
        // lineNumbers: true,
        mode: 'javascript',
        // tabSize: 2,
        // indentWithTabs: true,
        // value: JSON.stringify(gon.config.initialData, 2, 2),
      },
    );
    editor.on('change', changeObject => {
      const {text} = changeObject;
      configDataNode.value = text;
    });

Here is my code.

Currently running into an issue with this.

const configDataNode = document.getElementById('config_data');
    const editor = CodeMirror.fromTextArea(
      document.getElementById('config_data_editor'),
      {
        // lineNumbers: true,
        mode: 'javascript',
        // tabSize: 2,
        // indentWithTabs: true,
        // value: JSON.stringify(gon.config.initialData, 2, 2),
      },
    );
    editor.on('change', changeObject => {
      const {text} = changeObject;
      configDataNode.value = text;
    });

Here is my code.

• javascript

Share Improve this question Follow edited Dec 25, 2020 at 14:14 Abdelsalam Shahlol 1,77911 gold badge2424 silver badges3333 bronze badges asked Dec 30, 2018 at 22:26 Overload119Overload119 5,42655 gold badges3232 silver badges3737 bronze badges

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2 Answers 2

Sorted by: Reset to default 7

It is happening due to TextArea object's value field is undefined and thus inside the CodeMirror codemirror.js library options.value is initialising the doc variable also undefined, and thus later in source modeOption is getting matched with doc child field (if the doc is undefined, how a object key may exists).

var textarea_editor = document.getElementById("RichTextArea");

// so explicitly assign value to textarea object.
textarea_editor.value = "";


this.editor = CodeMirror.fromTextArea(textarea_editor, {
     tabSize: 4,
     mode: 'text/plain',
     theme: 'default',
     lineNumbers: true,
     styleActiveSelected: true,
     styleActiveLine: true,
     indentWithTabs: true,
     matchBrackets: true,
     highlightMatches: true,
});

Hope this may help someone.

The issue was that document.getElementById('config_data_editor') is not a textarea.

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