如何将此函数带参数传递给settimeout? [英] How to pass this function into settimeout with parameters?

问题描述

var test = function(a, b) {   return a + b; }; 
setTimeout(test(2, 3), 3000);

它显示一些类型错误

推荐答案

至少有两种方法可以实现这一点.第一个只是在作为回调传递给 setTimout 的新匿名函数内触发 test 函数.

There are at least two ways to achieve this. The first one just fires the test function inside of a new anonymous function passed as callback to the setTimout.

第二个使用 .bind 来部分应用 test 函数.

The second one uses .bind to partially apply the test function.

var test = function(a, b) {
  console.log(a + b);
  return a + b;
};

setTimeout(() => {
  test(2, 3);
}, 3000);

setTimeout(test.bind(null, 2, 3), 3000);

如果你不喜欢 .bind 的第一个(在这种情况下毫无意义的)参数 null ，那么你可以使用一些为你提供的库部分应用程序功能，或者您可以编写自己的函数来执行部分应用程序.

And if you don't like the first (in this case meaningless) argument null of .bind as I do, then you can use some library that provides you with partial application functionality or you can write your own function that performs partial application.

const partial = (fn, ...firstArgs) => (...secondArgs) =>
  fn(...firstArgs, ...secondArgs);

var test = function(a, b) {
  console.log(a + b);
  return a + b;
};

setTimeout(partial(test, 2, 3), 3000);

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