suggest-css-hash-len.js

suggest-css-hash-len.js

/*
at webpack settings:

plugins: [
        ...plugins,
        new SuggestCssHashLen({
            instance: MyShortCssClasses,
            selectedHashLen: cssHashLen
        })
    ]
*/

class SuggestCssHashLen {
    constructor({ instance, selectedHashLen }) {
        this.instance = instance;
        this.selectedHashLen = selectedHashLen;
    }

    apply(compiler) {
        compiler.plugin('done', this.run);
    }

    run = () => {
        const { instance, selectedHashLen } = this;
        const data = instance.getStat();
        const matchLen = {};
        const base = {};

        Object.entries(data).forEach(([_, { name, test }]) => {
            for(let len = 1; len <= name.length; len += 1) {
                base[len] = base[len] || {};
                const hash = name.substr(0, len);

                if (base[len][hash]) {
                    matchLen[len] = matchLen[len] || 0;
                    matchLen[len] += 1;
                } else {
                    base[len][hash] = 1;
                }
            }
        });

        console.log();
        console.log('Suggest Minify Plugin');
        console.log('Matched length (len: number):', matchLen);

        if (matchLen[selectedHashLen]) {
            console.log(
                `🚫 You can't use selected hash length (${selectedHashLen}). Increase the hash length.`
            );
            console.log();
            process.exit(1);
        } else {
            console.log(`Selected hash length (${selectedHashLen}) is OK.`);

            if (!matchLen[selectedHashLen - 1]) {
                console.log(`🎉 You can decrease the hash length (${selectedHashLen} -> ${selectedHashLen - 1}).`);
            }

            console.log();
        }
    };
}

module.exports = SuggestCssHashLen;