add toBlob and toArrayBuffer methods to browser.js

lib/browser.js

@@ -5,10 +5,15 @@ const QRCode = require('./core/qrcode')
 const CanvasRenderer = require('./renderer/canvas')
 const SvgRenderer = require('./renderer/svg-tag.js')
 
+function renderFuncHasCallback (renderFunc) {
+  return renderFunc === CanvasRenderer.renderToBlob || renderFunc === CanvasRenderer.renderToArrayBuffer
+}
+
 function renderCanvas (renderFunc, canvas, text, opts, cb) {
   const args = [].slice.call(arguments, 1)
   const argsNum = args.length
   const isLastArgCb = typeof args[argsNum - 1] === 'function'
+  const renderFnHasCallback = renderFuncHasCallback(renderFunc)
 
   if (!isLastArgCb && !canPromise()) {
     throw new Error('Callback required as last argument')
@@ -51,7 +56,14 @@ function renderCanvas (renderFunc, canvas, text, opts, cb) {
     return new Promise(function (resolve, reject) {
       try {
         const data = QRCode.create(text, opts)
-        resolve(renderFunc(data, canvas, opts))
+        if (renderFnHasCallback) {
+          renderFunc(data, canvas, opts, (err, result) => {
+            if (err) reject(err)
+            else resolve(result)
+          })
+        } else {
+          resolve(renderFunc(data, canvas, opts))
+        }
       } catch (e) {
         reject(e)
       }
@@ -60,7 +72,11 @@ function renderCanvas (renderFunc, canvas, text, opts, cb) {
 
   try {
     const data = QRCode.create(text, opts)
-    cb(null, renderFunc(data, canvas, opts))
+    if (renderFnHasCallback) {
+      renderFunc(data, canvas, opts, cb)
+    } else {
+      cb(null, renderFunc(data, canvas, opts))
+    }
   } catch (e) {
     cb(e)
   }
@@ -69,6 +85,8 @@ function renderCanvas (renderFunc, canvas, text, opts, cb) {
 exports.create = QRCode.create
 exports.toCanvas = renderCanvas.bind(null, CanvasRenderer.render)
 exports.toDataURL = renderCanvas.bind(null, CanvasRenderer.renderToDataURL)
+exports.toBlob = renderCanvas.bind(null, CanvasRenderer.renderToBlob)
+exports.toArrayBuffer = renderCanvas.bind(null, CanvasRenderer.renderToArrayBuffer)
 
 // only svg for now.
 exports.toString = renderCanvas.bind(null, function (data, _, opts) {

lib/renderer/canvas.js

@@ -61,3 +61,53 @@ exports.renderToDataURL = function renderToDataURL (qrData, canvas, options) {
 
   return canvasEl.toDataURL(type, rendererOpts.quality)
 }
+
+exports.renderToBlob = function renderToBlob (qrData, canvas, options, callback) {
+  let opts = options
+
+  if (typeof opts === 'undefined' && (!canvas || !canvas.getContext)) {
+    opts = canvas
+    canvas = undefined
+  }
+
+  if (!opts) opts = {}
+
+  const canvasEl = exports.render(qrData, canvas, opts)
+  const type = opts.type || 'image/png'
+  const rendererOpts = opts.rendererOpts || {}
+
+  canvasEl.toBlob((blobOrNull) => {
+    if (blobOrNull === null) {
+      callback(new Error('Failed to get canvas as blob'))
+    } else {
+      callback(null, blobOrNull)
+    }
+  }, type, rendererOpts.quality)
+}
+
+exports.renderToArrayBuffer = function renderToArrayBuffer (qrData, canvas, options, callback) {
+  let opts = options
+
+  if (typeof opts === 'undefined' && (!canvas || !canvas.getContext)) {
+    opts = canvas
+    canvas = undefined
+  }
+
+  if (!opts) opts = {}
+
+  const canvasEl = exports.render(qrData, canvas, opts)
+  const type = opts.type || 'image/png'
+
+  canvasEl.toBlob(async (blobOrNull) => {
+    if (blobOrNull === null) {
+      callback(new Error('Failed to get canvas as blob'))
+    } else {
+      try {
+        const arrayBuffer = await blobOrNull.arrayBuffer()
+        callback(null, arrayBuffer)
+      } catch (e) {
+        callback(e)
+      }
+    }
+  }, type, opts.rendererOpts.quality)
+}