You can update .prettierrc.json and set option trailingComma to none like:

{
  "trailingComma" : "none",
  ...
}

JavaScript has allowed trailing commas in array literals since the beginning, and later added them to object literals (ECMAScript 5) and most recently (ECMAScript 2017) to function parameters.

This is a relatively new change in syntax, but the basic idea is that by putting a comma on each line allows for:

1. Easier to add an item or re-order items. Before you always had to check the trailing comma and make sure it was present or removed depending on location.
2. Removes the need to have one line item be special because it lacks the ,.
3. Allows for cleaner Git diffs.

You can read up on the full documentation if you like - it goes into further detail: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Trailing_commas

As far as the issue with your chart not displaying, unless you are using a very old browser, a trailing comma should not cause an error/information to not display.

Change your .prettierrc file so that it looks like this:

    // "./.prettierrc"
    {
        "printWidth": 80,
        "singleQuote": true,
        "trailingComma": "all",
    }

Add the following setting, configured as it is below, to your ESLint Rules property that's inside of your .eslintrc.json file.

    // "./.eslintrc.json"
    {
        "comma-dangle": ["error", "always"],

    }

or you can just turn the rule off

    // "./.eslintrc.json"
    {
        "comma-dangle": 0
    }

Another option you have, if your using VSCode, is to use the ESLint-Prettier extension, rather than than using the ESLint Plugins as dependencies. The VSCode extension will not have a conflict in this situation.

The reason there is a conflict here is because it is a formatting rule, and ESLint's formatting rules interfere with JavaScript formatters like prettier.