Configuration option is out of date in "Rollup.js Tutorial, Part 1: How to Set Up Smaller, More Efficient JavaScript Bundling Using Rollup"

What's wrong?

The rollup.config.js in the tutorial is out of date.

Error Steps

The tutorial, Rollup.js Tutorial, Part 1: How to Set Up Smaller, More Efficient JavaScript Bundling Using Rollup using the following configuration option fails

export default {
  entry: "src/scripts/main.js",
  dest: "build/js/main.min.js",
  format: "iife",
  sourceMap: "inline"
};

with following messages.

dance2die@CC c:\misc\sources\throwaway\rollupdemo\learn-rollup
> .\node_modules\.bin\rollup -c
(!) Some options have been renamed
https://gist.github.com/Rich-Harris/d472c50732dab03efeb37472b08a3f32
entry is now input
sourceMap is now output.sourcemap
format is now output.format
dest is now output.file

src/scripts/main.js → build/js/main.min.js...
[!] Error: You must specify options.format, which can be one of 'amd', 'cjs', 'system', 'es', 'iife' or 'umd'
https://rollupjs.org/#format-f-output-format-
Error: You must specify options.format, which can be one of 'amd', 'cjs', 'system', 'es', 'iife' or 'umd'
    at error (c:\misc\sources\throwaway\rollupdemo\learn-rollup\node_modules\rollup\dist\rollup.js:224:15)
    at checkOutputOptions (c:\misc\sources\throwaway\rollupdemo\learn-rollup\node_modules\rollup\dist\rollup.js:19531:9)
    at normalizeOptions (c:\misc\sources\throwaway\rollupdemo\learn-rollup\node_modules\rollup\dist\rollup.js:19603:21)
    at generate (c:\misc\sources\throwaway\rollupdemo\learn-rollup\node_modules\rollup\dist\rollup.js:19607:41)
    at Object.write (c:\misc\sources\throwaway\rollupdemo\learn-rollup\node_modules\rollup\dist\rollup.js:19638:32)
    at c:\misc\sources\throwaway\rollupdemo\learn-rollup\node_modules\rollup\bin\rollup:3430:77
    at next (c:\misc\sources\throwaway\rollupdemo\learn-rollup\node_modules\rollup\bin\rollup:3371:32)
    at c:\misc\sources\throwaway\rollupdemo\learn-rollup\node_modules\rollup\bin\rollup:3374:53
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:182:7)

How to fix it

Rollup.JS documentation has a different format for the rollup.config.js and the following works for the tutorial

export default {
  input: "src/scripts/main.js",
  output: {
    file: "build/js/main.min.js",
    format: "iife",
    sourceMap: "inline"
  }
};

With the new configuration above,

Rollup Version

"rollup": "^0.57.1"