| Leo Repp | 58b9f11 | 2021-11-22 11:57:47 +0100 | [diff] [blame^] | 1 | 'use strict'; |
| 2 | |
| 3 | var callBound = require('call-bind/callBound'); |
| 4 | |
| 5 | var $PromiseThen = callBound('Promise.prototype.then', true); |
| 6 | |
| 7 | var Type = require('./Type'); |
| 8 | |
| 9 | // https://ecma-international.org/ecma-262/6.0/#sec-ispromise |
| 10 | |
| 11 | module.exports = function IsPromise(x) { |
| 12 | if (Type(x) !== 'Object') { |
| 13 | return false; |
| 14 | } |
| 15 | if (!$PromiseThen) { // Promises are not supported |
| 16 | return false; |
| 17 | } |
| 18 | try { |
| 19 | $PromiseThen(x); // throws if not a promise |
| 20 | } catch (e) { |
| 21 | return false; |
| 22 | } |
| 23 | return true; |
| 24 | }; |