[Interesting question] Determine if an object is a Promise object

First look at small right teacher is how to do

Check whether the object hasthenandcatchmethods

There’s another way to do it

You can borrow the original toString method

Interesting prototyping approach

Object.prototype.toString.call(new RegExp())
"[object RegExp]"
Object.prototype.toString.call(new Date())
"[object Date]"
Object.prototype.toString.call(new String())
"[object String]"
Object.prototype.toString.call(new Number())
"[object Number]"
Object.prototype.toString.call(Math)
"[object Math]"
Object.prototype.toString.call(new Error())
"[object Error]"
Object.prototype.toString.call(Symbol())
"[object Symbol]"
Object.prototype.toString.call(' ')
"[object String]"
Object.prototype.toString.call(0)
"[object Number]"
Object.prototype.toString.call(/ ^ 1 $/)
"[object RegExp]"
Object.prototype.toString.call(new Boolean())
"[object Boolean]"
Object.prototype.toString.call(true)
"[object Boolean]"
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