refactor: async/await

- https://dev.to/gafi/7-reasons-to-always-use-async-await-over-plain-promises-tutorial-4ej9
- https://stackoverflow.com/a/56975197

lib/filter.js

@@ -5,6 +5,8 @@ const CleanCSS = require('clean-css')
 const Terser = require('terser')
 const Svgo = require('svgo')
 const zlib = require('zlib')
+const { promisify } = require('util')
+const gzip = promisify(zlib.gzip)
 const br = require('iltorb')
 const micromatch = require('micromatch')
 
@@ -25,7 +27,6 @@ function verbose (original, minified, path, ext) {
 function minifyHtml (str, data) {
   const hexo = this
   const options = hexo.config.minify.html
-  // Return if disabled.
   if (options.enable === false) return
 
   const { path } = data
@@ -44,7 +45,7 @@ function minifyHtml (str, data) {
   return result
 }
 
-function minifyCss (str, data) {
+async function minifyCss (str, data) {
   const hexo = this
   const options = hexo.config.minify.css
   if (options.enable === false) return
@@ -58,13 +59,13 @@ function minifyCss (str, data) {
 
   if (isMatch(path, exclude, globOptions)) return str
 
-  return new Promise((resolve, reject) => {
-    new CleanCSS(options).minify(str, (err, result) => {
-      if (err) return reject(err)
+  try {
+    const result = await new CleanCSS(options).minify(str)
     if (options.logger) verbose.call(this, str, result.styles, path, 'css')
-      resolve(result.styles)
-    })
-  })
+    return result.styles
+  } catch (err) {
+    throw new Error(err)
+  }
 }
 
 function minifyJs (str, data) {
@@ -97,7 +98,6 @@ function minifyJs (str, data) {
 function minifySvg () {
   const hexo = this
   const options = hexo.config.minify.svg
-  // Return if disabled.
   if (options.enable === false) return
 
   const { route } = hexo
@@ -115,17 +115,16 @@ function minifySvg () {
       let assetTxt = ''
       // Extract the content
       assetPath.on('data', (chunk) => (assetTxt += chunk))
-      assetPath.on('end', () => {
+      assetPath.on('end', async () => {
         if (assetTxt.length) {
-          // Minify using svgo
-          new Svgo(options).optimize(assetTxt).then((result) => {
-            // Replace the original file with the minified.
-            route.set(path, result.data)
-
+          try {
+            const result = await new Svgo(options).optimize(assetTxt)
             if (options.logger) verbose.call(this, assetTxt, result.data, path, 'svg')
-
-            resolve(assetTxt)
-          })
+            resolve(route.set(path, result.data))
+          } catch (err) {
+            reject(err)
+            throw new Error(err)
+          }
         }
       })
     })
@@ -135,7 +134,6 @@ function minifySvg () {
 function gzipFn () {
   const hexo = this
   const options = hexo.config.minify.gzip
-  // Return if disabled.
   if (options.enable === false) return
 
   const { route } = hexo
@@ -153,21 +151,17 @@ function gzipFn () {
       let assetTxt = ''
       // Extract the content
       assetPath.on('data', (chunk) => (assetTxt += chunk))
-      assetPath.on('end', () => {
+      assetPath.on('end', async () => {
         if (assetTxt.length) {
+          try {
             // gzip compress using highest level
-          zlib.gzip(assetTxt, { level: zlib.constants.Z_BEST_COMPRESSION }, (err, Input) => {
-            if (!err) {
-              // Save the compressed file to .gz
-              route.set(path + '.gz', Input)
-
-              if (options.logger) verbose.call(this, assetTxt, Input.toString(), path, 'gzip')
-
-              resolve(assetTxt)
-            } else {
+            const result = await gzip(assetTxt, { level: zlib.constants.Z_BEST_COMPRESSION })
+            if (options.logger) verbose.call(this, assetTxt, result.toString(), path, 'gzip')
+            resolve(route.set(path + '.gz', result))
+          } catch (err) {
             reject(err)
+            throw new Error(err)
           }
-          })
         }
       })
     })
@@ -177,7 +171,6 @@ function gzipFn () {
 function brotliFn () {
   const hexo = this
   const options = hexo.config.minify.brotli
-  // Return if disabled.
   if (options.enable === false) return
 
   const { route } = hexo
@@ -195,23 +188,19 @@ function brotliFn () {
       let assetTxt = ''
       // Extract the content
       assetPath.on('data', (chunk) => (assetTxt += chunk))
-      assetPath.on('end', () => {
+      assetPath.on('end', async () => {
         if (assetTxt.length) {
-          // Input has to be buffer for brotli
+          // Input has to be buffer
           const input = Buffer.from(assetTxt, 'utf-8')
-          // brotli defaults to max compression level
-          br.compress(input, (err, output) => {
-            if (!err) {
-              // Save the compressed file to .br
-              route.set(path + '.br', output)
 
-              if (options.logger) verbose.call(this, input, output.toString(), path, 'brotli')
-
-              resolve(assetTxt)
-            } else {
+          try {
+            const result = await br.compress(input)
+            if (options.logger) verbose.call(this, input, result.toString(), path, 'brotli')
+            resolve(route.set(path + '.br', result))
+          } catch (err) {
             reject(err)
+            throw new Error(err)
           }
-          })
         }
       })
     })