Webpack compilation error with defaultOptions

[thalen]

• Operating System: MacOS 10.13.6
• Cypress Version: 3.1.1 (cypress-webpack-preprocessor 4.0.0)
• Browser Version: N/A
• Other: react-scripts 2.0.4 (which provides webpack 4 and babel 7)

Is this a Feature or Bug?

Bug, fails to run cypress tests

Current behavior:

When using the defaultOptions for webpack the presets is set to a string, but babel validates this as an array:

Error: Webpack Compilation Error at assertArray (/node_modules/@babel/core/lib/config/validation/option-assertions.js:150:11) at assertPluginList (/node_modules/@babel/core/lib/config/validation/option-assertions.js:219:15) at Object.keys.forEach.key (/node_modules/@babel/core/lib/config/validation/options.js:107:5) at Array.forEach (<anonymous>) at validateNested (/node_modules/@babel/core/lib/config/validation/options.js:83:21) at validate (/node_modules/@babel/core/lib/config/validation/options.js:74:10) at loadPrivatePartialConfig (/node_modules/@babel/core/lib/config/partial.js:66:50) at Object.loadPartialConfig (/node_modules/@babel/core/lib/config/partial.js:110:18)

Desired behavior:

The presets should be set to an array in defaultOptions, my current workaround is to fix this in plugins/index.js:

const webpack = require('@cypress/webpack-preprocessor');

module.exports = (on) => {
    const options = webpack.defaultOptions;
    options.webpackOptions.module.rules[0].use[0].options.presets = [options.webpackOptions.module.rules[0].use[0].options.presets];
    on('file:preprocessor', webpack(options))
};

How to reproduce:

Add webpack-preprocessor as a dependency version 4.0.0, and use with CRA2 (create-react-app V2). CRA2 uses webpack 4.x and babel 7.x

Additional Info (images, stack traces, etc)

Commit where presets was changed from array to string:
22db72da03943f9e28237033935e1bf4d8dddf25

[chrisbreiding]

I believe this is addressed by #39.

[chrisbreiding]

Version 4.0.1 has been published to NPM. The full release note can be found at cypress-webpack-preprocessor/releases/tag/v4.0.1.

Tip: safely upgrade dependency @cypress/webpack-preprocessor in your project using next-update