v4.1.0 doesn't respect modules: false anymore

[cecilia-sanare]

Description

👋 Hey there! Some of my libraries ended up catching a breaking change in this library.

The change to add the new mainFields option also made it so that module
is no longer take into account when determining what fields to pull.

Simple Example

const resolve = require('rollup-plugin-node-resolve');

module.exports = {
    // The rest of my rollup configuration ...

    plugins: [
        resolve({
            module: false, // still results in `mainFields` = ['main', 'module']
            browser: true,

            extensions: ['.mjs', '.js', '.jsx', '.json', '.ts']
        })

        // The rest of my super cool plugins ...
    ]
}

Related Code

rollup-plugin-node-resolve/src/index.js

Lines 48 to 59 in 86905f4

	mainFields = ['module', 'main'];
	[['module', 'module'], ['jsnext', 'jsnext:main'], ['main', 'main']].forEach(([option, field]) => {
	if (option in options) {
	// eslint-disable-next-line no-console
	console.warn(`node-resolve: setting options.${option} is deprecated, please override options.mainFields instead`);
	if (options[option] === false) {
	mainFields = mainFields.filter(mainField => mainField === field);
	} else if (options[option] === true && mainFields.indexOf(field) === -1) {
	mainFields.push(field);
	}
	}
	});

Workaround

Just move to the new field since it works correctly.

[cecilia-sanare]

After digging into it a little bit more, it looks like:

mainFields = mainFields.filter(mainField => mainField === field); 

should be this:

mainFields = mainFields.filter(mainField => mainField !== field); 

EDIT: I've opened a PR to resolve this issue.