formikReactAce.js

import React from 'react';

import { Field } from 'formik';
import AceEditor from 'react-ace';

import 'brace/mode/ejs';
import 'brace/theme/textmate';

export const EjsForm = ({ name }) => (
  <Field name={name}>
    {({ field }) => (
      <React.Fragment>
        <AceEditor
          mode="ejs"
          theme="textmate"
          onChange={value => {
            field.onChange(name)(value);
          }}
          tabSize={2}
          editorProps={{ $blockScrolling: true }}
          value={field.value}
          width="100%"
        />
      </React.Fragment>
    )}
  </Field>
);