如何在javascript方法链中休眠方法 [英] How to sleep a method in javascript method chaining
问题描述
我正在尝试使方法链中的方法进入睡眠(延迟)状态.为此,我将 setTimeout
与 Promise
结合使用.这将要求 sleep
之后的任何方法都必须位于 then
之内.
I am trying to make a method sleep(delay) in method chaining. For this I am using setTimeout
with Promise
. This will require any method following the sleep
to be inside the then
.
现在我正在调用类似的函数
Right now I am calling the function like
lazyMan("John",console.log).eat("banana").sleep(5).then(d => {d.eat("apple");});
.
这是我的代码
function lazyMan(name, logFn) {
logFn(name);
return {
eat: function(val) {
console.log(val);
return this;
},
sleep: function(timer) {
return new Promise((resolve, reject) => {
setTimeout(() => {
console.log(`Sleeping for ${timer} seconds`);
resolve(this);
}, timer * 1000);
}).then(d => this);
}
};
}
lazyMan("John", console.log)
.eat("banana")
.sleep(5)
.then(d => {
d.eat("apple");
});
有没有一种方法可以修改我的函数以像 lazyMan("John",console.log).eat("banana").sleep(5).eat("apple")一样调用它.)
并以相同顺序获取输出
Is there a way I can modify my function to call it like lazyMan("John", console.log).eat("banana").sleep(5).eat("apple")
and get the output in same order
我已经通过在对象中添加sleep方法方法链(JS)
推荐答案
您可以保留对任务队列"的承诺,因此需要完成的所有操作都将通过添加到那里.)
.这提供了流畅的API来安排工作.
You can keep a promise for your "task queue", so anything that needs to be done, will be added onto there via .then()
. This provides a fluent API for scheduling stuff.
function lazyMan(name, logFn) {
logFn(name);
let taskQueue = Promise.resolve();
const addTask = f => {
taskQueue = taskQueue.then(f);
}
return {
eat: function(val) {
addTask(() => console.log(`Eating [${val}]`));
return this;
},
sleep: function(timer) {
addTask(() => new Promise((resolve, reject) => {
console.log(`Start sleeping for ${timer} seconds`);
setTimeout(() => {
console.log(`End sleeping for ${timer} seconds`);
resolve();
}, timer * 1000);
}))
return this;
}
};
}
lazyMan("John", console.log)
.eat("banana")
.sleep(5)
.eat("apple");
请注意,此更改意味着每个操作在技术上都是异步的.但是,这至少是统一的,因此牢记这一点的可能性很小.
Note that this change means that every action is technically asynchronous. However, that's at least uniform, so it's less of a chance of a surprise when keeping it in mind.
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