gulp-html-minifier-terser/index.js

Gulp plugin to minify HTML.

"use strict";

const { Transform } = require("node:stream");
const PluginError = require("plugin-error");
const htmlmin = require("html-minifier-terser");

function createPluginError(file, options, err) {
  return new PluginError(
    "gulp-html-minifier-terser",
    err,
    Object.assign({}, options, { fileName: file.path }),
  );
}

function createMinifyStream(file, options) {
  let chunks = [];

  return new Transform({
    transform(chunk, enc, cb) {
      chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk, enc));
      cb();
    },
    async flush(cb) {
      try {
        let html = Buffer.concat(chunks).toString();
        let minified = await htmlmin.minify(html, options);
        this.push(Buffer.from(minified));
        cb();
      } catch (err) {
        cb(createPluginError(file, options, err));
      }
    },
  });
}

module.exports = (options) => {
  return new Transform({
    objectMode: true,
    async transform(file, enc, next) {
      if (file.isNull()) {
        next(null, file);
        return;
      }

      if (file.isStream()) {
        let minifyStream = file.contents.pipe(createMinifyStream(file, options));
        minifyStream.on("error", (error) => this.emit("error", error));
        file.contents = minifyStream;
        next(null, file);
        return;
      }

      try {
        let minified = await htmlmin.minify(file.contents.toString(), options);
        file.contents = Buffer.from(minified);
        next(null, file);
      } catch (err) {
        next(createPluginError(file, options, err));
      }
    },
  });
};