有没有办法直接将数组项映射到typescript中的函数参数？

Question

I often end up with a situation where i got an array with arguments and have to manually break the array into parts. For example

Observable.combineLatest(obs1$, obs2$, obs3$).subscribe((data) => {
  let fancyArg = data[0];
  let epicArg = data[1];
  let wonderfulArg = data[2];
})

Is there a shortcut to do something like this

Observable.combineLatest(obs1$, obs2$, obs3$)
  .subscribe([fancyArg, epicArg, wonderfulArg] => { //something like this
    ...                                             //would be great
  })

I know that there is the option with the last argument as function

Observable.combineLatest(obs1$, obs2$, obs3$, 
  (arg1, arg2, arg3) => {
    return {
      fancyArg:arg1, 
      epicArg:arg2, 
      wonderfulArg:arg3
    }
  })
  .subscribe((args) => {
    ...
  })

but this is also very unhandy. I look for a more general approach (to use it by bindCallback and other functions as well)

Answer 1

Javascript has destructuring assignment which you can use in your parameter list to unpack an array. Example:

 function takeAnArray([firstItem, secondItem, thirdItem]) { console.log(firstItem, secondItem, thirdItem); } takeAnArray([1, "a", false]); 

So you were almost right in your second snippet. You just need to add a pair of parenthases around the argument list:

Observable.combineLatest(obs1$, obs2$, obs3$)
  .subscribe(([fancyArg, epicArg, wonderfulArg]) => {
    // Here, fancyArg is the first array element,
    // epicArg is the second
    // wonderfulArg is the third
  })

The documentation for combineLatest even shows this syntax in it's first example.