src.js

const CodeMirror = require('codemirror');

function codeMirrorBinder(config) {
    let instance;
    let changeCallback;

    return {
        on(callback) {
            changeCallback = callback;
            instance.on('change', changeCallback);
        },
        getValue() {
            instance.save();
            return instance.getValue();
        },
        setValue(value) {
            instance.setValue(value);
            instance.save();
        },
        initialize() {
            /* istanbul ignore if */
            if (!this.parentNode) {
                throw new Error('parentNode isn\'n found'
                    + ' you need to insert textarea into the document before binder use');
            }

            instance = CodeMirror.fromTextArea(this, config);
        },
        destroy() {
            instance.off('change', changeCallback);
            instance.toTextArea();
        }
    };
}

module.exports = codeMirrorBinder;