H5

framework/4-queue.js

@@ -0,0 +1,61 @@
+const checkConcurrency = (concurrency = 1) => {
+    if (concurrency == null) {
+        concurrency = 1
+    }
+    else if (concurrency === 0) {
+        throw new Error('Concurrency must not be zero')
+    }
+    return concurrency
+}
+
+const onlyOnce = (fn) => (...args) => {
+    if (fn === null) {
+        throw new Error('Callback was already called')
+    }
+    const callFn = fn
+    fn = null
+    return callFn(...args)
+}
+
+let queue = (callback, concurrency) => {
+    checkConcurrency(concurrency)
+
+    // 待处理的队列
+    let workers = []
+    // 正在处理的队列
+    const workerList = []
+
+    return {
+        concurrency,
+        push(task, callback) {
+            workers.push({
+                task,
+                callback,
+            })
+            setTimeout(() => {
+                this.process()
+            }, 0)
+        },
+        process() {
+            while (this.concurrency > workerList.length && workers.length) {
+                const worker = workers.shift()
+                workerList.push(worker)
+                callback(worker.task, onlyOnce((...args) => {
+                    this.pull(worker)
+                    if (typeof worker.callback === 'function') {
+                        worker.callback(...args)
+                    }
+                    this.process()
+                }))
+            }
+        },
+        pull(worker) {
+            const index = workerList.indexOf(worker)
+            if (index !== -1) {
+                workerList.splice(index, 1)
+            }
+        }
+    }
+}
+
+uni.queue = queue((task, callback) => task(callback), 10)