HarmonyOS 应用开发之@Concurrent装饰器：声明并校验并发函数_harmonyos ts concurrent is not defined(2)

2401_83947105

742人浏览 · 2024-04-09 20:43:30

2401_83947105 · 2024-04-09 20:43:30 发布

说明：
并发函数中返回Promise的表现需关注，其中并发同步函数会处理返回该Promise并返回结果。

示例：

import taskpool from ‘@ohos.taskpool’;

@Concurrent
function testPromise(args1: number, args2: number): Promise {
return new Promise((testFuncA, testFuncB)=>{
testFuncA(args1 + args2);
});
}

@Concurrent
async function testPromise1(args1: number, args2: number): Promise {
return new Promise((testFuncA, testFuncB)=>{
testFuncA(args1 + args2);
});
}

@Concurrent
async function testPromise2(args1: number, args2: number): Promise {
return await new Promise((testFuncA, testFuncB)=>{
testFuncA(args1 + args2)
});
}

@Concurrent
function testPromise3() {
return Promise.resolve(1);
}

@Concurrent
async function testPromise4(): Promise {
return 1;
}

@Concurrent
async function testPromise5(): Promise {
return await new Promise((resolve) => {
setTimeout(()=>{
resolve(“Promise setTimeout after resolve”);
}, 1000)
});
}

async function testConcurrentFunc() {
let task1: taskpool.Task = new taskpool.Task(testPromise, 1, 2);
let task2: taskpool.Task = new taskpool.Task(testPromise1, 1, 2);
let task3: taskpool.Task = new taskpool.Task(testPromise2, 1, 2);
let task4: taskpool.Task = new taskpool.Task(testPromise3);
let task5: taskpool.Task = new taskpool.Task(testPromise4);
let task6: taskpool.Task = new taskpool.Task(testPromise5);

taskpool.execute(task1).then((d:object)=>{
console.info("task1 res is: " + d)
}).catch((e:object)=>{
console.info("task1 catch e: " + e)
})
taskpool.execute(task2).then((d:object)=>{
console.info("task2 res is: " + d)
}).catch((e:object)=>{
console.info("task2 catch e: " + e)
})
taskpool.execute(task3).then((d:object)=>{
console.info("task3 res is: " + d)
}).catch((e:object)=>{
console.info("task3 catch e: " + e)
})
taskpool.execute(task4).then((d:object)=>{
console.info("task4 res is: " + d)
}).catch((e:object)=>{
console.info("task4 catch e: " + e)
})
taskpool.execute(task5).then((d:object)=>{
console.info("task5 res is: " + d)
}).catch((e:object)=>{
console.info("task5 catch e: " + e)
})
taskpool.execute(task6).then((d:object)=>{
console.info("task6 res is: " + d)
}).catch((e:object)=>{
console.info("task6 catch e: " + e)
})
}

testConcurrentFunc();

输出结果如下所示：

task1 res is: 3
task2 catch e: Error: Can’t return Promise in pending state
task3 res is: 3
task4 res is: 1
task5 res is: 1
task6 res is: Promise setTimeout after resolve

说明：
并发异步方法中如果使用Promise，建议搭配await使用捕获Promise中可能发生的异常。推荐使用示例如下。

示例：

@Concurrent
async function testPromiseError() {
await new Promise((resolve, reject) => {
resolve(1);
}).then(()=>{
throw new Error(“testPromise Error”);
})
}

@Concurrent
async function testPromiseError1() {
await new Promise((resolve, reject) => {
reject(“testPromiseError1 Error msg”);
})
}

@Concurrent
function testPromiseError2() {
return new Promise((resolve, reject) => {
reject(“testPromiseError2 Error msg”);
})
}

async function testConcurrentFunc() {
let task1: taskpool.Task = new taskpool.Task(testPromiseError);
let task2: taskpool.Task = new taskpool.Task(testPromiseError1);
let task3: taskpool.Task = new taskpool.Task(testPromiseError2);