diff --git a/index.js b/index.js
index e96b968..3d03cea 100644
--- a/index.js
+++ b/index.js
@@ -1,10 +1,10 @@
+const path = require('path');
 const chalk = require('chalk');
 const PluginError = require('plugin-error');
 const replaceExtension = require('replace-ext');
 const stripAnsi = require('strip-ansi');
 const transfob = require('transfob');
 const clonedeep = require('lodash.clonedeep');
-const path = require('path');
 const applySourceMap = require('vinyl-sourcemaps-apply');
 
 const PLUGIN_NAME = 'gulp-sass';
@@ -21,7 +21,7 @@ const gulpSass = (options, sync) => transfob((file, enc, cb) => { // eslint-disa
     return cb(new PluginError(PLUGIN_NAME, 'Streaming not supported'));
   }
 
-  if (path.basename(file.path).indexOf('_') === 0) {
+  if (path.basename(file.path).startsWith('_')) {
     return cb();
   }
 
diff --git a/test/main.js b/test/main.js
index d7739a9..284f119 100644
--- a/test/main.js
+++ b/test/main.js
@@ -1,7 +1,7 @@
+const fs = require('fs');
+const path = require('path');
 const should = require('should');
 const Vinyl = require('vinyl');
-const path = require('path');
-const fs = require('fs');
 const rimraf = require('rimraf');
 const gulp = require('gulp');
 const sourcemaps = require('gulp-sourcemaps');
@@ -107,7 +107,7 @@ describe('gulp-sass -- async compile', () => {
       should.exist(cssFile.path);
       should.exist(cssFile.relative);
       should.exist(cssFile.contents);
-      if (cssFile.path.indexOf('variables') !== -1) {
+      if (cssFile.path.includes('variables')) {
         expectedPath = path.join('expected', 'variables.css');
       }
 
@@ -156,11 +156,11 @@ describe('gulp-sass -- async compile', () => {
 
     stream.on('error', (err) => {
       // Error must include message body
-      err.message.indexOf('property "font" must be followed by a \':\'').should.not.equal(-1);
+      err.message.includes('property "font" must be followed by a \':\'').should.equal(true);
       // Error must include file error occurs in
-      err.message.indexOf('test', 'scss', 'error.scss').should.not.equal(-1);
+      err.message.includes('test', 'scss', 'error.scss').should.equal(true);
       // Error must include line and column error occurs on
-      err.message.indexOf('on line 2').should.not.equal(-1);
+      err.message.includes('on line 2').should.equal(true);
       // Error must include relativePath property
       err.relativePath.should.equal(path.join('test', 'scss', 'error.scss'));
       done();
@@ -174,9 +174,9 @@ describe('gulp-sass -- async compile', () => {
 
     stream.on('error', (err) => {
       // Error must include original error message
-      err.messageOriginal.indexOf('property "font" must be followed by a \':\'').should.not.equal(-1);
+      err.messageOriginal.includes('property "font" must be followed by a \':\'').should.equal(true);
       // Error must not format or change the original error message
-      err.messageOriginal.indexOf('on line 2').should.equal(-1);
+      err.messageOriginal.includes('on line 2').should.equal(false);
       done();
     });
     stream.write(errorFile);
@@ -280,7 +280,7 @@ describe('gulp-sass -- async compile', () => {
       should.exist(cssFile.path);
       should.exist(cssFile.relative);
       should.exist(cssFile.contents);
-      if (cssFile.path.indexOf('indent') !== -1) {
+      if (cssFile.path.includes('indent')) {
         expectedPath = path.join('expected', 'indent.css');
       }
 
@@ -360,7 +360,7 @@ describe('gulp-sass -- sync compile', () => {
       should.exist(cssFile.relative);
       should.exist(cssFile.contents);
 
-      if (cssFile.path.indexOf('variables') !== -1) {
+      if (cssFile.path.includes('variables')) {
         expectedPath = path.join('expected', 'variables.css');
       }
 
@@ -400,7 +400,7 @@ describe('gulp-sass -- sync compile', () => {
     const stream = sass.sync();
 
     stream.on('error', (err) => {
-      err.message.indexOf('property "font" must be followed by a \':\'').should.not.equal(-1);
+      err.message.includes('property "font" must be followed by a \':\'').should.equal(true);
       err.relativePath.should.equal(path.join('test', 'scss', 'error.scss'));
       done();
     });