UTF16 to UTF8

1. utf16 to utf8: Convert from UTF-16, allows to encode Hanji, Kanji, emoji, etc.
1. clear build dir.

package.json

@@ -13,7 +13,7 @@
     "build:es": "cross-env NODE_ENV=es rollup -c",
     "build:umd": "cross-env NODE_ENV=development rollup -c",
     "build:umd:min": "cross-env NODE_ENV=production rollup -c",
-    "build": "npm run build:es && npm run build:umd && npm run build:umd:min",
+    "build": "npm run clean && npm run build:es && npm run build:umd && npm run build:umd:min",
     "lint": "eslint --ext .js,.vue src",
     "prepublish": "npm run build"
   },

rollup.config.js

@@ -15,6 +15,8 @@ const banner =
   '\n * © 2017-' + new Date().getFullYear() + ' @scopewu' +
   '\n * MIT License.' +
   '\n */'
+const sourcemap = false
+const indent = false
 
 const config = {
   input: 'src/index.js',
@@ -64,7 +66,8 @@ if (env === 'es') {
     file: 'dist/qrcode.vue.esm.js',
     format: 'es',
     name: 'QrcodeVue',
-    sourcemap: false,
+    sourcemap,
+    indent,
     banner
   }
 }
@@ -74,7 +77,8 @@ if (env === 'development') {
     file: 'dist/qrcode.vue.js',
     format: 'umd',
     name: 'QrcodeVue',
-    sourcemap: false,
+    sourcemap,
+    indent,
     banner
   }
 }

src/index.js

@@ -12,6 +12,41 @@ function getBackingStorePixelRatio(ctx) {
   )
 }
 
+/**
+ * Encode UTF16 to UTF8.
+ * See: http://jonisalonen.com/2012/from-utf-16-to-utf-8-in-javascript/
+ * @param str {string}
+ * @returns {string}
+ */
+function toUTF8String(str) {
+  let utf8Str = ''
+  for (let i = 0; i < str.length; i++) {
+    let charCode = str.charCodeAt(i)
+    if (charCode < 0x0080) {
+      utf8Str += String.fromCharCode(charCode)
+    } else if (charCode < 0x0800) {
+      utf8Str += String.fromCharCode(0xc0 | (charCode >> 6))
+      utf8Str += String.fromCharCode(0x80 | (charCode & 0x3f))
+    } else if (charCode < 0xd800 || charCode >= 0xe000) {
+      utf8Str += String.fromCharCode(0xe0 | (charCode >> 12))
+      utf8Str += String.fromCharCode(0x80 | ((charCode >> 6) & 0x3f))
+      utf8Str += String.fromCharCode(0x80 | (charCode & 0x3f))
+    } else {
+      // surrogate pair
+      i++
+      // UTF-16 encodes 0x10000-0x10FFFF by
+      // subtracting 0x10000 and splitting the
+      // 20 bits of 0x0-0xFFFFF into two halves
+      charCode = 0x10000 + (((charCode & 0x3ff) << 10) | (str.charCodeAt(i) & 0x3ff))
+      utf8Str += String.fromCharCode(0xf0 | (charCode >> 18))
+      utf8Str += String.fromCharCode(0x80 | ((charCode >> 12) & 0x3f))
+      utf8Str += String.fromCharCode(0x80 | ((charCode >> 6) & 0x3f))
+      utf8Str += String.fromCharCode(0x80 | (charCode & 0x3f))
+    }
+  }
+  return utf8Str
+}
+
 const QrcodeVue = {
   render(createElement) {
     const {className, value, level, background, foreground, size} = this
@@ -71,7 +106,7 @@ const QrcodeVue = {
 
       // We'll use type===-1 to force QRCode to automatically pick the best type
       const qrCode = new QRCode(-1, ErrorCorrectLevel[level])
-      qrCode.addData(value)
+      qrCode.addData(toUTF8String(value))
       qrCode.make()
 
       const canvas = this.$refs['qrcode-vue']