Use async I/O functions

1 files changed, 39 insertions, 21 deletions

diff --git a/scripts/frontend/prettier.js b/scripts/frontend/prettier.js
index d76b83add26..4e42e682d35 100644
--- a/scripts/frontend/prettier.js
+++ b/scripts/frontend/prettier.js
@@ -85,6 +85,22 @@ let passedCount = 0;
 let failedCount = 0;
 let ignoredCount = 0;
 
+const readFileAsync = (file, options) =>
+  new Promise((resolve, reject) => {
+    fs.readFile(file, options, function(err, data) {
+      if (err) reject(err);
+      else resolve(data);
+    });
+  });
+
+const writeFileAsync = (file, data, options) =>
+  new Promise((resolve, reject) => {
+    fs.writeFile(file, data, options, function(err) {
+      if (err) reject(err);
+      else resolve();
+    });
+  });
+
 const FIX_COMMAND = `yarn prettier-${allFiles ? 'all' : 'staged'}-save`;
 const WARNING_MESSAGE = `
 ===============================
@@ -101,30 +117,32 @@ Promise.all(
         return;
       }
       return prettier.resolveConfig(filePath).then(fileOptions => {
-        const options = { ...fileOptions, parser: inferredParser };
-        const input = fs.readFileSync(filePath, 'utf8');
-
-        if (shouldSave) {
-          const output = prettier.format(input, options);
-          if (input === output) {
-            passedCount += 1;
-          } else {
-            fs.writeFileSync(filePath, output, 'utf8');
-            console.log(`Prettified : ${filePath}`);
-            failedCount += 1;
-          }
-        } else {
-          if (prettier.check(input, options)) {
-            passedCount += 1;
+        return readFileAsync(filePath, 'utf8').then(input => {
+          const options = { ...fileOptions, parser: inferredParser };
+
+          if (shouldSave) {
+            const output = prettier.format(input, options);
+            if (input === output) {
+              passedCount += 1;
+            } else {
+              return writeFileAsync(filePath, output, 'utf8').then(() => {
+                console.log(`Prettified : ${filePath}`);
+                failedCount += 1;
+              });
+            }
           } else {
-            if (!didWarn) {
-              console.log(WARNING_MESSAGE);
-              didWarn = true;
+            if (prettier.check(input, options)) {
+              passedCount += 1;
+            } else {
+              if (!didWarn) {
+                console.log(WARNING_MESSAGE);
+                didWarn = true;
+              }
+              console.log(`Prettify Manually : ${filePath}`);
+              failedCount += 1;
             }
-            console.log(`Prettify Manually : ${filePath}`);
-            failedCount += 1;
           }
-        }
+        });
       });
     })
   )