diff --git a/src/index.js b/src/index.js
index 3bbf4bb..231b029 100644
--- a/src/index.js
+++ b/src/index.js
@@ -2,6 +2,7 @@
 
 import path from 'path'
 import SingleEntryPlugin from 'webpack/lib/SingleEntryPlugin'
+import createHash from 'webpack/lib/util/createHash'
 import minimatch from 'minimatch'
 
 function validatePaths(assets, options) {
@@ -24,6 +25,18 @@ function validatePaths(assets, options) {
   })
 }
 
+function hash(source, outputOptions) {
+  const hashFunction = outputOptions.hashFunction
+  const hashDigest = outputOptions.hashDigest
+  const hashDigestLength = outputOptions.hashDigestLength
+  const hash = createHash(hashFunction)
+  if (outputOptions.hashSalt) {
+    hash.update(outputOptions.hashSalt)
+  }
+  hash.update(source)
+  return hash.digest(hashDigest).substr(0, hashDigestLength)
+}
+
 const COMPILER_NAME = 'serviceworker-plugin'
 
 export default class ServiceWorkerPlugin {
@@ -176,8 +189,11 @@ export default class ServiceWorkerPlugin {
 
     assets = validatePaths(assets, this.options)
 
+    const assetsHash = hash(JSON.stringify(assets), compilation.options.output)
+
     const serviceWorkerOption = this.options.transformOptions({
       assets,
+      assetsHash,
       jsonStats,
     })
 
diff --git a/src/index.spec.js b/src/index.spec.js
index b0477d4..97e4173 100644
--- a/src/index.spec.js
+++ b/src/index.spec.js
@@ -14,6 +14,13 @@ function trim(str) {
 
 const filename = 'sw.js'
 const webpackOutputPath = path.resolve('./tmp-build')
+const outputOptions = {
+  path: webpackOutputPath,
+  // these are the defaults from https://github.com/webpack/webpack/blob/master/lib/WebpackOptionsDefaulter.js#L164
+  hashFunction: 'md4',
+  hashDigest: 'hex',
+  hashDigestLength: 20,
+}
 const makeWebpackConfig = options => ({
   entry: path.join(__dirname, '../test/test-build-entry'),
   mode: 'development',
@@ -29,10 +36,9 @@ const makeWebpackConfig = options => ({
       'serviceworker-webpack-plugin/lib/runtime': path.join(__dirname, 'runtime.js'),
     },
   },
-  output: {
-    path: webpackOutputPath,
-  },
+  output: outputOptions,
 })
+const fakeOptions = { output: outputOptions }
 
 describe('ServiceWorkerPlugin', () => {
   beforeEach(done => {
@@ -96,6 +102,7 @@ describe('ServiceWorkerPlugin', () => {
       })
 
       const compilation = {
+        options: fakeOptions,
         assets: {
           [filename]: {
             source: () => '',
@@ -140,6 +147,7 @@ var serviceWorkerOption = {
         })
 
         const compilation = {
+          options: fakeOptions,
           assets: {
             [filename]: {
               source: () => '',
@@ -170,7 +178,73 @@ var serviceWorkerOption = {
             )
           }
         )
-      })
+      }),
+        it('should get passed assetsHash', done => {
+          const transformOptions = serviceWorkerOption => {
+            expect(serviceWorkerOption)
+              .to.have.property('assetsHash')
+              .that.is.equal('bd90271e0847dcc66adb')
+          }
+
+          const serviceWorkerPlugin = new ServiceWorkerPlugin({
+            filename,
+            transformOptions,
+          })
+
+          const compilation = {
+            options: fakeOptions,
+            assets: {
+              [filename]: {
+                source: () => '',
+              },
+              'bar-v1.js': {},
+            },
+            getStats: () => ({
+              toJson: () => ({}),
+            }),
+          }
+
+          return serviceWorkerPlugin.handleEmit(
+            compilation,
+            {
+              options: {},
+            },
+            done
+          )
+        }),
+        it('should change assetsHash when filename changes', done => {
+          const transformOptions = serviceWorkerOption => {
+            expect(serviceWorkerOption)
+              .to.have.property('assetsHash')
+              .that.is.equal('47633aad38a6adaca6ec')
+          }
+
+          const serviceWorkerPlugin = new ServiceWorkerPlugin({
+            filename,
+            transformOptions,
+          })
+
+          const compilation = {
+            options: fakeOptions,
+            assets: {
+              [filename]: {
+                source: () => '',
+              },
+              'bar-v2.js': {},
+            },
+            getStats: () => ({
+              toJson: () => ({}),
+            }),
+          }
+
+          return serviceWorkerPlugin.handleEmit(
+            compilation,
+            {
+              options: {},
+            },
+            done
+          )
+        })
     })
   })
 })