difference between “Promise reject” with “try-catch”

Question

var promise = new Promise(function(resolve, reject) {
  try {
    throw new Error('test');
  } catch(e) {
    reject(e);
  }
});
promise.catch(function(error) {
  console.log(error);
});

we can use "try-catch" to throw error

// mothod 2
var promise = new Promise(function(resolve, reject) {
  reject(new Error('test'));
});
promise.catch(function(error) {
  console.log(error);
});

we also can use "reject" to throw error.

what's difference between them?

You [should never use `try`/`catch` inside a promise callback](http://stackoverflow.com/a/42650428/1048572) — Bergi, Mar 16 '17 at 05:02

score 2 · Accepted Answer · answered Mar 16 '17 at 04:23

2

Exceptions thrown from asynchronous functions cannot be handled with try-catch block.
Promises are chain-able; prevents us from nesting code that affects readability.

answered Mar 16 '17 at 04:23

Bethleharaja G

44
3

score 0 · Answer 2 · answered Mar 16 '17 at 04:22

There is no effective difference. In both cases, you're calling reject() with an error.

The following are also equivalent to what you have there:

var promise = new Promise(function(resolve, reject) {
  throw new Error('test');
});


var promise = Promise.reject(new Error('test'));


var promise = Promise.resolve().then(function () { throw new Error('test'); });

difference between “Promise reject” with “try-catch”

2 Answers2