test: improve logic

lib/prefetch/ChunkPrefetchPreloadPlugin.js

@@ -107,7 +107,10 @@ class ChunkPrefetchPreloadPlugin {
 
 									if (
 										chunksFetchPriorityMap[c.id] &&
-										prefetchOrder > chunksFetchPriorityMap[c.id].prefetchOrder
+										prefetchOrder &&
+										(chunksFetchPriorityMap[c.id].prefetchOrder === undefined ||
+											prefetchOrder >
+												chunksFetchPriorityMap[c.id].prefetchOrder)
 									) {
 										chunksFetchPriorityMap[c.id] = {
 											fetchPriority,
@@ -116,7 +119,7 @@ class ChunkPrefetchPreloadPlugin {
 									} else if (!chunksFetchPriorityMap[c.id]) {
 										chunksFetchPriorityMap[c.id] = {
 											fetchPriority,
-											prefetchOrder: prefetchOrder || 0
+											prefetchOrder: prefetchOrder
 										};
 									}
 								});

test/configCases/web/fetch-priority-2/d.js

@@ -0,0 +1,3 @@
+export default function test() {
+	import("./d1");
+}

test/configCases/web/fetch-priority-2/d1.js

@@ -0,0 +1,3 @@
+export default function test() {
+	import("./d2");
+}

test/configCases/web/fetch-priority-2/d2.js

@@ -0,0 +1,3 @@
+export default function test() {
+	import(/* webpackFetchPriority: "high" */ "./d3");
+}

test/configCases/web/fetch-priority-2/d3.js

@@ -0,0 +1 @@
+export default "d3";

test/configCases/web/fetch-priority-2/index.js

@@ -1,18 +1,28 @@
 it("should set fetchPriority", () => {
-	import("./a");
-	expect(document.head._children).toHaveLength(3);
-	const script1 = document.head._children[1];
-	expect(script1._attributes.fetchpriority).toBe("low");
-
-	import("./b");
+	import(/* webpackFetchPriority: "high" */ "./a");
 	expect(document.head._children).toHaveLength(4);
-	const script2 = document.head._children[3];
+	const script1 = document.head._children[2];
+	expect(script1._attributes.fetchpriority).toBe("high");
+
+	import(/* webpackFetchPriority: "low" */ "./b");
+	expect(document.head._children).toHaveLength(5);
+	const script2 = document.head._children[4];
 	expect(script2._attributes.fetchpriority).toBe("low");
 
-	import( "./c");
-	expect(document.head._children).toHaveLength(5);
-	const script3 = document.head._children[4];
+	import(/* webpackFetchPriority: "low" */ "./c");
+	expect(document.head._children).toHaveLength(6);
+	const script3 = document.head._children[5];
 	expect(script3._attributes.fetchpriority).toBe("auto");
 
 	import(/* webpackPrefetch: 20, webpackFetchPriority: "auto" */ "./c");
+
+	import("./d")
+	expect(document.head._children).toHaveLength(7);
+	const script4 = document.head._children[6];
+	expect(script4._attributes.fetchpriority).toBeUndefined();
+
+	import(/* webpackPrefetch: -20 */ "./d3");
+	expect(document.head._children).toHaveLength(8);
+	const script5 = document.head._children[7];
+	expect(script5._attributes.fetchpriority).toBe("high");
 });

test/configCases/web/fetch-priority-2/webpack.config.js

@@ -12,10 +12,15 @@ module.exports = {
 		}
 	},
 	module: {
-		parser: {
-			javascript: {
-				dynamicImportFetchPriority: "low"
+		rules: [
+			{
+				test: /d\.js$/,
+				parser: {
+					javascript: {
+						dynamicImportFetchPriority: "low"
+					}
+				}
 			}
-		}
+		]
 	}
 };