Use arrow functions for callbacks

server/middleware/utils/createMutex.js

@@ -13,7 +13,7 @@ function createMutex(doWork) {
       ]
 
       doWork(payload, function(error, value) {
-        mutex[key].forEach(function(callback) {
+        mutex[key].forEach(callback => {
           callback(error, value)
         })
       })

server/middleware/utils/createSearch.js

@@ -1,7 +1,7 @@
 function createSearch(query) {
   const params = []
 
-  Object.keys(query).forEach(function(param) {
+  Object.keys(query).forEach(param => {
     if (query[param] === '') {
       params.push(param) // Omit the trailing "=" from param=
     } else {

server/middleware/utils/getIndexHTML.js

@@ -8,7 +8,7 @@ const IndexPage = require('../components/IndexPage')
 const e = React.createElement
 
 function getEntries(dir) {
-  return new Promise(function(resolve, reject) {
+  return new Promise((resolve, reject) => {
     fs.readdir(dir, function(error, files) {
       if (error) {
         reject(error)
@@ -16,8 +16,8 @@ function getEntries(dir) {
         resolve(
           Promise.all(
             files.map(file => getFileStats(path.join(dir, file)))
-          ).then(function(statsArray) {
-            return statsArray.map(function(stats, index) {
+          ).then(statsArray => {
+            return statsArray.map((stats, index) => {
               return { file: files[index], stats }
             })
           })

server/middleware/utils/getMetadata.js

@@ -6,26 +6,24 @@ const getFileStats = require('./getFileStats')
 const getFileType = require('./getFileType')
 
 function getEntries(dir, file, maximumDepth) {
-  return new Promise(function(resolve, reject) {
+  return new Promise((resolve, reject) => {
     fs.readdir(path.join(dir, file), function(error, files) {
       if (error) {
         reject(error)
       } else {
         resolve(
           Promise.all(
-            files.map(function(f) {
-              return getFileStats(path.join(dir, file, f))
-            })
-          ).then(function(statsArray) {
+            files.map(f => getFileStats(path.join(dir, file, f)))
+          ).then(statsArray => {
             return Promise.all(
-              statsArray.map(function(stats, index) {
-                return getMetadataRecursive(
+              statsArray.map((stats, index) =>
+                getMetadataRecursive(
                   dir,
                   path.join(file, files[index]),
                   stats,
                   maximumDepth - 1
                 )
-              })
+              )
             )
           })
         )
@@ -39,7 +37,7 @@ function formatTime(time) {
 }
 
 function getIntegrity(file) {
-  return new Promise(function(resolve, reject) {
+  return new Promise((resolve, reject) => {
     fs.readFile(file, function(error, data) {
       if (error) {
         reject(error)
@@ -60,7 +58,7 @@ function getMetadataRecursive(dir, file, stats, maximumDepth) {
   }
 
   if (stats.isFile()) {
-    return getIntegrity(path.join(dir, file)).then(function(integrity) {
+    return getIntegrity(path.join(dir, file)).then(integrity => {
       metadata.integrity = integrity
       return metadata
     })
@@ -69,7 +67,7 @@ function getMetadataRecursive(dir, file, stats, maximumDepth) {
   if (!stats.isDirectory() || maximumDepth === 0)
     return Promise.resolve(metadata)
 
-  return getEntries(dir, file, maximumDepth).then(function(files) {
+  return getEntries(dir, file, maximumDepth).then(files => {
     metadata.files = files
     return metadata
   })

server/middleware/utils/getPackage.js

@@ -26,7 +26,7 @@ function ignoreSymlinks(file, headers) {
 }
 
 function extractResponse(response, outputDir) {
-  return new Promise(function(resolve, reject) {
+  return new Promise((resolve, reject) => {
     const extract = tar.extract(outputDir, {
       readable: true, // All dirs/files should be readable.
       map: stripNamePrefix,
@@ -44,12 +44,12 @@ function extractResponse(response, outputDir) {
 function fetchAndExtract(tarballURL, outputDir) {
   console.log(`info: Fetching ${tarballURL} and extracting to ${outputDir}`)
 
-  return fetch(tarballURL).then(function(response) {
+  return fetch(tarballURL).then(response => {
     return extractResponse(response, outputDir)
   })
 }
 
-const fetchMutex = createMutex(function(payload, callback) {
+const fetchMutex = createMutex((payload, callback) => {
   const { tarballURL, outputDir } = payload
 
   fs.access(outputDir, function(error) {
@@ -61,7 +61,7 @@ const fetchMutex = createMutex(function(payload, callback) {
           if (error) {
             callback(error)
           } else {
-            fetchAndExtract(tarballURL, outputDir).then(function() {
+            fetchAndExtract(tarballURL, outputDir).then(() => {
               callback()
             }, callback)
           }

server/middleware/utils/getPackageInfo.js

@@ -22,7 +22,7 @@ function fetchPackageInfo(packageName) {
     headers: {
       Accept: 'application/json'
     }
-  }).then(function(res) {
+  }).then(res => {
     return res.status === 404 ? null : res.json()
   })
 }
@@ -31,7 +31,7 @@ const PackageNotFound = 'PackageNotFound'
 
 // This mutex prevents multiple concurrent requests to
 // the registry for the same package info.
-const fetchMutex = createMutex(function(packageName, callback) {
+const fetchMutex = createMutex((packageName, callback) => {
   fetchPackageInfo(packageName).then(
     function(value) {
       if (value == null) {