[英]typescript - create a callback function
hey guys i'd like to know how to make a callback function in typescript. 大家好,我想知道如何在打字稿中制作一个回调函数。
I know how to do it in vanilla JS : 我知道如何在香草JS中做到这一点:
function mySandwich(param1, param2, callback) {
alert('Started eating my sandwich.\n\nIt has: ' + param1 + ', ' + param2);
callback();}
mySandwich('ham', 'cheese', function() {
alert('Finished eating my sandwich.');});
But i can't find a way to do it with TS. 但是我找不到用TS做到这一点的方法。 you guys have an example of it? 你们有一个例子吗?
thank you! 谢谢!
Typescript is a superset of javascript, so any javascript code is valid typescript code. Typescript是javascript的超集,因此任何javascript代码都是有效的Typescript代码。
But you can use types for safety: 但是为了安全起见,可以使用类型:
function mySandwich(param1: string, param2: string, callback: () => void) {
alert('Started eating my sandwich.\n\nIt has: ' + param1 + ', ' + param2);
callback();
}
mySandwich('ham', 'cheese', function() {
alert('Finished eating my sandwich.');
});
mySandwich('ham'); // Error: Supplied parameters do not match any signature of call target
mySandwich('ham', 'cheese', (num: number) => 4 * num); // Error: Argument of type '(num: number) => number' is not assignable to parameter of type '() => void'
( code in playground ) ( 操场上的代码 )
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