minifier.js

var fs = require("fs");
var minify = require("html-minifier").minify;

var filePath = "dist/index.html";

fs.readFile(filePath, function (err, buf) {
    if (err) {
        console.log(err);
    } else {
        var originalValue = buf.toString();
        var minifiedValue = minify(originalValue, {
            caseSensitive: false,
            collapseBooleanAttributes: true,
            collapseInlineTagWhitespace: false,
            collapseWhitespace: true,
            conservativeCollapse: false,
            decodeEntities: true,
            html5: true,
            includeAutoGeneratedTags: false,
            keepClosingSlash: false,
            minifyCSS: true,
            minifyJS: true,
            preserveLineBreaks: false,
            preventAttributesEscaping: false,
            processConditionalComments: true,
            processScripts: ["text/html"],
            removeAttributeQuotes: true,
            removeComments: true,
            removeEmptyAttributes: true,
            removeEmptyElements: false,
            removeOptionalTags: true,
            removeRedundantAttributes: true,
            removeScriptTypeAttributes: true,
            removeStyleLinkTypeAttributes: true,
            removeTagWhitespace: true,
            sortAttributes: true,
            sortClassName: true,
            trimCustomFragments: true,
            useShortDoctype: true,
        });

        fs.writeFile(filePath, minifiedValue, function (err, data) {
            if (err) {
                console.log(err);
            } else {
                var diff = originalValue.length - minifiedValue.length;
                var savings = originalValue.length
                    ? ((100 * diff) / originalValue.length).toFixed(2)
                    : 0;
                console.log(
                    "Successfully minified '" +
                        filePath +
                        "'" +
                        ". Original size: " +
                        originalValue.length +
                        ". Minified size: " +
                        minifiedValue.length +
                        ". Savings: " +
                        diff +
                        " (" +
                        savings +
                        "%)"
                );
            }
        });
    }
});