Revision of Async-1.js

1 file changed, 24 insertions

Async-1.js(檔案已創建)

		@@ -0,0 +1,24 @@
1	+	// for use with callbacks...
2	+	import { forEachOf } from "async-es";
3	+
4	+	const images = {cat: "/cat.png", dog: "/dog.png", duck: "/duck.png"};
5	+	const sizes = {};
6	+
7	+	forEachOf(images, (value, key, callback) => {
8	+	const imageElem = new Image();
9	+	imageElem.src = value;
10	+	imageElem.addEventListener("load", () => {
11	+	sizes[key] = {
12	+	width: imageElem.naturalWidth,
13	+	height: imageElem.naturalHeight,
14	+	};
15	+	callback();
16	+	});
17	+	imageElem.addEventListener("error", (e) => {
18	+	callback(e);
19	+	});
20	+	}, err => {
21	+	if (err) console.error(err.message);
22	+	// `sizes` is now a map of image sizes
23	+	doSomethingWith(sizes);
24	+	});