From 4b25d109dde7be663284fb40d6c66951a32fe246 Mon Sep 17 00:00:00 2001
From: ferferga <ferferga.fer@gmail.com>
Date: Tue, 20 Oct 2020 00:14:55 +0200
Subject: [PATCH] feat(blurhash): Move blurhash decoding to web worker

---
 components/BlurhashCanvas.vue | 27 ++++++++++++++++++---------
 components/blurhash.worker.ts |  8 ++++++++
 nuxt.config.ts                | 10 ++++++++++
 package.json                  |  3 ++-
 tsconfig.json                 | 21 +++++++++++++++++----
 vue-shims.d.ts                |  8 ++++++++
 yarn.lock                     | 29 ++++++++++++++++++++++++++++-
 7 files changed, 91 insertions(+), 15 deletions(-)
 create mode 100644 components/blurhash.worker.ts

diff --git a/components/BlurhashCanvas.vue b/components/BlurhashCanvas.vue
index 000f250b..de851635 100644
--- a/components/BlurhashCanvas.vue
+++ b/components/BlurhashCanvas.vue
@@ -4,7 +4,8 @@
 
 <script lang="ts">
 import Vue from 'vue';
-import { decode } from 'blurhash';
+import Worker from 'worker-loader!./blurhash.worker';
+const worker = new Worker();
 
 export default Vue.extend({
   props: {
@@ -37,15 +38,23 @@ export default Vue.extend({
   },
   methods: {
     draw() {
-      const pixels = decode(this.hash, this.width, this.height);
-      if (pixels) {
-        const ctx = (this.$refs.canvas as HTMLCanvasElement).getContext('2d');
-        const imageData = ctx?.createImageData(this.width, this.height);
-        if (imageData) {
-          imageData.data.set(pixels);
-          ctx?.putImageData(imageData, 0, 0);
+      const bhash_data = {
+        hash: this.hash,
+        width: this.width,
+        height: this.height
+      };
+      worker.postMessage(bhash_data);
+      worker.onmessage = ({ data }) => {
+        const pixels = data;
+        if (pixels) {
+          const ctx = (this.$refs.canvas as HTMLCanvasElement).getContext('2d');
+          const imageData = ctx?.createImageData(this.width, this.height);
+          if (imageData) {
+            imageData.data.set(pixels);
+            ctx?.putImageData(imageData, 0, 0);
+          }
         }
-      }
+      };
     }
   }
 });
diff --git a/components/blurhash.worker.ts b/components/blurhash.worker.ts
new file mode 100644
index 00000000..072e0087
--- /dev/null
+++ b/components/blurhash.worker.ts
@@ -0,0 +1,8 @@
+import { decode } from 'blurhash';
+
+const ctx: Worker = self as any;
+ctx.addEventListener('message', event => {
+    const data = event.data;
+    const pixels = decode(data.hash, data.width, data.height);
+    ctx.postMessage({ pixels });
+});
diff --git a/nuxt.config.ts b/nuxt.config.ts
index 2cf051de..60545a3c 100644
--- a/nuxt.config.ts
+++ b/nuxt.config.ts
@@ -224,6 +224,16 @@ const config: NuxtConfig = {
           ]
         ];
       }
+    },
+    extend(config, { isDev, isClient }) {
+      // Web Worker support
+      if (isClient) {
+        config.module.rules.push({
+          test: /\.worker\.js$/,
+          use: { loader: 'worker-loader' },
+          exclude: /(node_modules)/
+        })
+      }
     }
   },
 
diff --git a/package.json b/package.json
index 017df4e5..03a82e65 100644
--- a/package.json
+++ b/package.json
@@ -76,7 +76,8 @@
     "stylelint-config-standard": "^20.0.0",
     "ts-jest": "^26.4.1",
     "ts-loader": "^8.0.5",
-    "vue-jest": "^3.0.7"
+    "vue-jest": "^3.0.7",
+    "worker-loader": "^3.0.5"
   },
   "config": {
     "commitizen": {
diff --git a/tsconfig.json b/tsconfig.json
index 0c99bdb1..7aaa4cfb 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -3,7 +3,12 @@
     "target": "ES2018",
     "module": "ESNext",
     "moduleResolution": "Node",
-    "lib": ["ESNext", "ESNext.AsyncIterable", "DOM"],
+    "lib": [
+      "ESNext",
+      "ESNext.AsyncIterable",
+      "DOM",
+      "webworker"
+    ],
     "esModuleInterop": true,
     "allowJs": true,
     "sourceMap": true,
@@ -12,8 +17,12 @@
     "experimentalDecorators": true,
     "baseUrl": ".",
     "paths": {
-      "~/*": ["./*"],
-      "@/*": ["./*"]
+      "~/*": [
+        "./*"
+      ],
+      "@/*": [
+        "./*"
+      ]
     },
     "types": [
       "@types/node",
@@ -25,5 +34,9 @@
       "jest"
     ]
   },
-  "exclude": ["node_modules", ".nuxt", "dist"]
+  "exclude": [
+    "node_modules",
+    ".nuxt",
+    "dist"
+  ]
 }
diff --git a/vue-shims.d.ts b/vue-shims.d.ts
index 54244845..eb5700e8 100644
--- a/vue-shims.d.ts
+++ b/vue-shims.d.ts
@@ -3,3 +3,11 @@ declare module '*.vue' {
 
   export default Vue;
 }
+
+declare module "worker-loader!*" {
+  class WebpackWorker extends Worker {
+    constructor();
+  }
+
+  export default WebpackWorker;
+}
diff --git a/yarn.lock b/yarn.lock
index 0ceeb7ac..f54ca66f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2087,7 +2087,7 @@
     jest-diff "^25.2.1"
     pretty-format "^25.2.1"
 
-"@types/json-schema@*", "@types/json-schema@^7.0.3", "@types/json-schema@^7.0.4", "@types/json-schema@^7.0.5":
+"@types/json-schema@*", "@types/json-schema@^7.0.3", "@types/json-schema@^7.0.4", "@types/json-schema@^7.0.5", "@types/json-schema@^7.0.6":
   version "7.0.6"
   resolved "https://registry.yarnpkg.com/@types/json-schema/-/json-schema-7.0.6.tgz#f4c7ec43e81b319a9815115031709f26987891f0"
   integrity sha512-3c+yGKvVP5Y9TYBEibGNR+kLtijnj7mYrXRg+WpFb2X9xm04g/DXYkfg4hmzJQosc9snFNUPkbYIhu+KAm6jJw==
@@ -2718,6 +2718,16 @@ ajv@^6.1.0, ajv@^6.10.0, ajv@^6.10.2, ajv@^6.12.2, ajv@^6.12.3, ajv@^6.12.4:
     json-schema-traverse "^0.4.1"
     uri-js "^4.2.2"
 
+ajv@^6.12.5:
+  version "6.12.6"
+  resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.12.6.tgz#baf5a62e802b07d977034586f8c3baf5adf26df4"
+  integrity sha512-j3fVLgvTo527anyYyJOGTYJbG+vnnQYvE0m5mmkc1TK+nxAppkCLMIL0aZ4dblVCNoGShhm+kzE4ZUykBoMg4g==
+  dependencies:
+    fast-deep-equal "^3.1.1"
+    fast-json-stable-stringify "^2.0.0"
+    json-schema-traverse "^0.4.1"
+    uri-js "^4.2.2"
+
 alphanum-sort@^1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/alphanum-sort/-/alphanum-sort-1.0.2.tgz#97a1119649b211ad33691d9f9f486a8ec9fbe0a3"
@@ -11094,6 +11104,15 @@ schema-utils@^2.0.0, schema-utils@^2.5.0, schema-utils@^2.6.1, schema-utils@^2.6
     ajv "^6.12.4"
     ajv-keywords "^3.5.2"
 
+schema-utils@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/schema-utils/-/schema-utils-3.0.0.tgz#67502f6aa2b66a2d4032b4279a2944978a0913ef"
+  integrity sha512-6D82/xSzO094ajanoOSbe4YvXWMfn2A//8Y1+MUqFAJul5Bs+yn36xbK9OtNDcRVSBJ9jjeoXftM6CfztsjOAA==
+  dependencies:
+    "@types/json-schema" "^7.0.6"
+    ajv "^6.12.5"
+    ajv-keywords "^3.5.2"
+
 scrollparent@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/scrollparent/-/scrollparent-2.0.1.tgz#715d5b9cc57760fb22bdccc3befb5bfe06b1a317"
@@ -13084,6 +13103,14 @@ worker-farm@^1.7.0:
   dependencies:
     errno "~0.1.7"
 
+worker-loader@^3.0.5:
+  version "3.0.5"
+  resolved "https://registry.yarnpkg.com/worker-loader/-/worker-loader-3.0.5.tgz#6e13a583c4120ba419eece8e4f2e098b014311bf"
+  integrity sha512-cOh4UqTtvT8eHpyuuTK2C66Fg/G5Pb7g11bwtKm7uyD0vj2hCGY1APlSzVD75V9ciYZt44VPbFPiSFTSLxkQ+w==
+  dependencies:
+    loader-utils "^2.0.0"
+    schema-utils "^3.0.0"
+
 wrap-ansi@^6.0.0, wrap-ansi@^6.2.0:
   version "6.2.0"
   resolved "https://registry.yarnpkg.com/wrap-ansi/-/wrap-ansi-6.2.0.tgz#e9393ba07102e6c91a3b221478f0257cd2856e53"