diff --git a/.gitignore b/.gitignore
index 5c49d4c..f6d83d4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ coverage/
 tmp/
 npm-debug.log*
 .DS_Store
+.nyc_output/
diff --git a/.travis.yml b/.travis.yml
index eb5b6c6..d3e8bac 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,18 @@
-node_js:
-  - stable
-  - 9
-  - 6
-  - 4
-sudo: false
+os: linux
+dist: bionic
 language: node_js
+node_js:
+  - 12
+  - 10
+  - 8
 script: "npm run test:cov"
-after_script: "npm i -g codecov.io && cat ./coverage/lcov.info | codecov"
+
+jobs:
+  include:
+    - node_js: stable
+      after_script: |
+        npm i -g codecov
+        npx nyc report --reporter=text-lcov | codecov --pipe
+    # Node.js 6 is not supported by nyc, so run tests without code coverage
+    - node_js: 6
+      script: npm run test
diff --git a/index.js b/index.js
index 289f646..473099b 100644
--- a/index.js
+++ b/index.js
@@ -16,8 +16,8 @@ function cssExtract (bundle, opts) {
   var outFile = opts.out || opts.o || 'bundle.css'
   var sourceMap = d(opts.sourceMap, bundle && bundle._options && bundle._options.debug, false)
 
-  assert.equal(typeof bundle, 'object', 'bundle should be an object')
-  assert.equal(typeof opts, 'object', 'opts should be an object')
+  assert.strictEqual(typeof bundle, 'object', 'bundle should be an object')
+  assert.strictEqual(typeof opts, 'object', 'opts should be an object')
 
   // every time .bundle is called, attach hook
   bundle.on('reset', addHooks)
diff --git a/package.json b/package.json
index c142119..fb44f81 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,7 @@
   "scripts": {
     "deps": "dependency-check . && dependency-check . --extra --no-dev",
     "test": "standard && npm run deps && NODE_ENV=test node test",
-    "test:cov": "standard && npm run deps && NODE_ENV=test istanbul cover ./test/index.js"
+    "test:cov": "standard && npm run deps && NODE_ENV=test nyc node test"
   },
   "repository": "stackcss/css-extract",
   "keywords": [
@@ -20,21 +20,21 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "bl": "^1.1.2",
+    "bl": "^4.0.2",
     "defined": "^1.0.0",
     "from2-string": "^1.1.0",
     "static-module": "^3.0.0",
-    "through2": "^2.0.1"
+    "through2": "^4.0.2"
   },
   "devDependencies": {
-    "browserify": "^13.0.0",
-    "dependency-check": "^2.5.1",
+    "browserify": "^16.5.2",
+    "dependency-check": "^2.10.1",
     "insert-css": "^2.0.0",
-    "istanbul": "^0.4.2",
-    "sheetify": "^6.0.0",
-    "standard": "^6.0.7",
-    "tape": "^4.5.0",
-    "tmp": "0.0.28"
+    "nyc": "^15.1.0",
+    "sheetify": "^8.0.0",
+    "standard": "^14.3.4",
+    "tape": "^5.0.1",
+    "tmp": "^0.2.1"
   },
   "files": [
     "index.js",
diff --git a/test/index.js b/test/index.js
index 1afa789..bb788d8 100644
--- a/test/index.js
+++ b/test/index.js
@@ -33,7 +33,7 @@ test('css-extract', function (t) {
 
   t.test('should extract sheetify css to file', function (t) {
     t.plan(3)
-    tmpDir({unsafeCleanup: true}, onDir)
+    tmpDir({ unsafeCleanup: true }, onDir)
 
     function onDir (err, dir, cleanup) {
       t.ifError(err, 'no error')