[英]Define Callback in interface Typescript
I want to implement an interface with a list of functions and attributes, few functions required to work on callback mode.我想实现一个带有函数和属性列表的接口,在回调模式下工作所需的函数很少。 For example例如
interface Writer{
readData : (fileLocation: string) => void;
generatData: (fileLocation: string) => void;
}
I would like to execute generateData function and notify after job is done.我想执行 generateData function 并在工作完成后通知。 For example例如
const WriterInstance:Writer ={
generateData("C:/workspace" , ()=>{
console.log("work is done");
});
readData("C:/workspace/file1.text" , ()=>{
console.log("work is done");
})
}
I am totally misunderstanding the syntax & invocation of callbacks in the interface.我完全误解了接口中回调的语法和调用。 If anyone explains with example then it will be great.如果有人举例说明,那就太好了。
In your interface, you want to represent a function with two parameters, the first one is a string and the second one is a function so you can write it like that:在你的界面中,你想用两个参数表示一个 function,第一个是字符串,第二个是 function,所以你可以这样写:
interface Writer{
readData : (fileLocation: string, callback: ()=>void) => void;
generateData: (fileLocation: string, callback: ()=>void) => void;
}
Just imagine that the callback function is a normal parameter.试想一下,回调 function 是一个普通参数。 Then, define WriterInstance
as a normal object - Just define it's properties然后,将WriterInstance
定义为普通的 object - 只需定义它的属性
interface Writer{
readData : (fileLocation: string, callback: () => void) => void;
generateData: (fileLocation: string, callback: (error: Error, data?: any) => void) => void;
}
const WriterInstance: Writer = {
readData: (fileLocation: string, callback: () => void) => {
// dome something with fileLocation
callback();
},
generateData: (fileLocation: string, callback: (error: Error, data?: any) => void) => {
// dome something with fileLocation
callback(null, true);
}
}
// usage of WriterInstance
WriterInstance.generateData('C:/workspace/file1.text', (error, data) => {
if (error) {
console.log('work is not done');
return console.log(error);
}
console.log('work is done');
});
// Define writer interface
interface Writer{
readData : (fileLocation: string, callback: () => void) => void;
generateData: (fileLocation: string, callback: () => void) => void;
}
// Create writer
const writerInstance: Writer = {
generateData: (fileLocation: string, callback: () => void) => {
// generate data
callback();
},
readData: (fileLocation: string, callback: () => void) => {
//read data
callback();
}
}
// Call writer methods
writerInstance.generateData("C:/workspace", ()=>{
console.log("work is done");
});
writerInstance.readData("C:/workspace/file1.text" , ()=>{
console.log("work is done");
});
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