diff --git a/package.json b/package.json
index 6fc0f9178..5a5ace432 100644
--- a/package.json
+++ b/package.json
@@ -74,7 +74,7 @@
     "eslint-plugin-react": "7.7.0",
     "jest": "21.1.0",
     "mkdirp": "0.5.1",
-    "prettier": "1.12.1",
+    "prettier": "1.13.0",
     "prettylint": "1.0.0",
     "rimraf": "2.6.2",
     "rollup": "0.47.6",
diff --git a/scripts/build-docs.js b/scripts/build-docs.js
index daf521b84..0d4583763 100644
--- a/scripts/build-docs.js
+++ b/scripts/build-docs.js
@@ -2,7 +2,6 @@
 
 "use strict";
 
-const fs = require("fs");
 const path = require("path");
 const shell = require("shelljs");
 
@@ -10,8 +9,6 @@ const rootDir = path.join(__dirname, "..", "..");
 const staticDir = path.join(rootDir, "website/static");
 const docs = path.join(rootDir, "website/static/lib");
 
-const stripLanguageDirectory = parserPath => parserPath.replace(/.*\//, "");
-
 function pipe(string) {
   return new shell.ShellString(string);
 }
diff --git a/src/common/util.js b/src/common/util.js
index f21c1117e..8bf14d98c 100644
--- a/src/common/util.js
+++ b/src/common/util.js
@@ -439,7 +439,7 @@ function getAlignmentSize(value, tabWidth, startIndex) {
       // multiple of tabWidth:
       // 0 -> 4, 1 -> 4, 2 -> 4, 3 -> 4
       // 4 -> 8, 5 -> 8, 6 -> 8, 7 -> 8 ...
-      size = size + tabWidth - size % tabWidth;
+      size = size + tabWidth - (size % tabWidth);
     } else {
       size++;
     }
diff --git a/yarn.lock b/yarn.lock
index 20b6f7ed6..38ec11434 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4435,9 +4435,9 @@ preserve@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
 
-prettier@1.12.1:
-  version "1.12.1"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.12.1.tgz#c1ad20e803e7749faf905a409d2367e06bbe7325"
+prettier@1.13.0:
+  version "1.13.0"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.13.0.tgz#054de8d5fb1a4405c845d16183f58a2c301f6f16"
 
 pretty-format@21.3.0-beta.15:
   version "21.3.0-beta.15"