Fabric.JS不处理承诺或回调
Fabric.JS不处理承诺或回调
提问于 2018-05-15 14:22:33
因此，我使用一个名为fabric.js (Node.JS，而不是针对浏览器)的Node.JS/NPM库，这是一种奇怪的方法。
//Make a new Canvas object (`fabric.createCanvasForNode` is not a constructor)
var canvas = new fabric.StaticCanvas(null, {width: 200, height: 200})
//Make a new Rectangle
var rect = new fabric.Rect({
left: 100,
top: 100,
width: 100,
height: 50,
fill: "red"
})
//Put the Rectangle on the Canvas
canvas.add(rect)
//Save the image as a PNG
canvas.createPNGStream().pipe(fs.createWriteStream(__dirname + "/output.png"))唯一的问题是，canvas.add()是一个函数，应该返回一个承诺，但它不是即时的，但它并不适用于承诺(canvas.add(...).then() is not a function)。我试过的下一件事是回调。我试过：
canvas.add(rect, function (err, canvas) {
console.log("working")
})随同
canvas.add(rect, function () {
console.log("working")
})但两者都犯了以下错误：
C:\Users\me\Documents\my project\node_modules\fabric\dist\fabric.js:3696
obj._set("canvas", this);
^
TypeError: obj._set is not a function
at klass._onObjectAdded (C:\Users\me\Documents\my project\node_modules\fabric\dist\fabric.js:3696:17)
at klass.add (C:\Users\me\Documents\my project\node_modules\fabric\dist\fabric.js:152:22)
at Client.client.on.message (C:\Users\me\Documents\my project\index.js:41:10)
at emitOne (events.js:115:13)
at Client.emit (events.js:210:7)
at MessageCreateHandler.handle (C:\Users\me\Documents\my project\node_modules\discord.js\src\client\websocket\packets\handlers\MessageCreate.js:9:34)
at WebSocketPacketManager.handle (C:\Users\me\Documents\my project\node_modules\discord.js\src\client\websocket\packets\WebSocketPacketManager.js:103:65)
at WebSocketConnection.onPacket (C:\Users\me\Documents\my project\node_modules\discord.js\src\client\websocket\WebSocketConnection.js:330:35)
at WebSocketConnection.onMessage (C:\Users\me\Documents\my project\node_modules\discord.js\src\client\websocket\WebSocketConnection.js:293:17)
at WebSocketClient.internalOnMessage (C:\Users\me\Documents\my project\node_modules\uws\uws.js:103:17)那我该怎么办？我用承诺和/或回调的方式做错了什么吗？难道布料根本就不能支撑它们吗？有什么解决办法吗？
回答 1
Stack Overflow用户
回答已采纳
发布于 2018-05-15 14:30:23
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原文链接：
https://stackoverflow.com/questions/50352663
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