Kotlin/JS TeserPlugin settings for optimization

webpack.js

// …
new TerserPlugin({
    terserOptions: {
        // ecma: "2016", // doesn't work with some libraries
        compress: {
            keep_fargs: false,
            negate_iife: false,
            passes: 5, // 4 was highest number observed to date that results in even smaller code
            pure_funcs(node) {
                // noinspection JSUnresolvedVariable
                return ![
                    'isObject',
                    'KClass',
                    'KClassImpl',
                    'KClassifier',
                    'Unit',
                    'Unit_getInstance',
                    'getKPropMetadata',
                    'getPropertyCallableRef',
                    'getPropertyRefClass',
                    'propertyRefClassMetadataCache$init$'
                ].includes(node.expression.name)
            },
            pure_getters: true,
            unsafe: true,
            unsafe_arrows: true,
            unsafe_methods: true,
            unsafe_proto: true,
            unsafe_symbols: true,
        },
        format: {
            beautify: false, // 'true' for debugging
            wrap_func_args: false,
            wrap_iife: true,
        },
        mangle: {
            keep_classnames: false, // 'true' for debugging
            keep_fnames: false, // 'true' for debugging
        },
    },
}),
// …