create-amp-page/htmlTask/cleanHtmlCss.js

Full fledged static side generator composed out of extendable gulp tasks, optimized for - but not limited to - AMP.

import {comb} from 'email-comb'
import through2 from 'through2'
import {minify as htmlmin} from 'html-minifier'
import logger from 'gulplog'

export function cleanHtmlCss(
    {
        cleanInlineCSS, cleanInlineCSSOptions, cleanInlineCSSWhitelist = [],
        minifyHtml, minifyHtmlOptions,
    },
) {
    return through2.obj(async (file, _, cb) => {
        try {
            let startHtmlCSSSize = null
            if((cleanInlineCSS || minifyHtml) && file.isBuffer()) {
                startHtmlCSSSize = Buffer.byteLength(file.contents.toString(), 'utf8')
                logger.info('HTML + CSS Size: ' + startHtmlCSSSize + ' bytes @' + (file.pathData || file.path).slice(file.cwd.length + 1))
            }
            let cleanedHtmlResult = null
            if(cleanInlineCSS && file.isBuffer()) {
                cleanedHtmlResult = comb(file.contents.toString(), cleanInlineCSSOptions || {
                    whitelist: cleanInlineCSSWhitelist,
                })
                file.contents = Buffer.from(cleanedHtmlResult.result)
            }
            if(minifyHtml && file.isBuffer()) {
                file.contents = Buffer.from(htmlmin(file.contents.toString(), minifyHtmlOptions || {
                    collapseBooleanAttributes: true,
                    collapseInlineTagWhitespace: false,
                    collapseWhitespace: true,
                    decodeEntities: true,
                    removeAttributeQuotes: true,
                }))
            }
            if((cleanInlineCSS || minifyHtml) && file.isBuffer()) {
                const cleanedHtmlCSSSize = Buffer.byteLength(file.contents.toString(), 'utf8')
                if(cleanedHtmlResult) {
                    logger.info('Removed CSS selectors: ' + cleanedHtmlResult.deletedFromBody.length + ' from body and ' + cleanedHtmlResult.deletedFromHead.length + ' from head')
                }
                logger.info('Cleaned HTML + CSS Size: ' + cleanedHtmlCSSSize + ' bytes, saved ' + (startHtmlCSSSize - cleanedHtmlCSSSize) + ' bytes @' + (file.pathData || file.path).slice(file.cwd.length))
            }
            cb(null, file)
        } catch(e) {
            cb(e)
        }
    })
}