Included as stated in readme but I get TypeError: cannot read proprty length of undefined

[SumNeuron]

Tried to include this in the tutorial from https://code.lengstorf.com/learn-rollup-js/ and got TypeError...

[sgnagnarella]

I am getting a similar error when turning on source maps.
This is my rollup.js file

`
import commonjs from "rollup-plugin-commonjs";
import obfuscatorPlugin from "rollup-plugin-javascript-obfuscator";

export default {
input: "src/main.js",
output: {
file: "build/main.js",
format: "cjs",
name: "fwi"
},
sourceMap: true,
sourceMapMode: "inline",
plugins: [
commonjs({
include: "node_modules/**"
}),
obfuscatorPlugin({
compact: true
})
]
};
`

And this is the error I get:

[!] TypeError: Cannot read property 'length' of undefined TypeError: Cannot read property 'length' of undefined at Link.traceMappings (/Users/sgnagnarella/Documents/SourceCode/pcshim/node_modules/rollup/dist/rollup.js:13559:54) at collapseSourcemaps (/Users/sgnagnarella/Documents/SourceCode/pcshim/node_modules/rollup/dist/rollup.js:13680:21) at /Users/sgnagnarella/Documents/SourceCode/pcshim/node_modules/rollup/dist/rollup.js:14946:27 at process._tickCallback (internal/process/next_tick.js:68:7) at Function.Module.runMain (internal/modules/cjs/loader.js:744:11) at startup (internal/bootstrap/node.js:285:19) at bootstrapNodeJSCore (internal/bootstrap/node.js:739:3)