Error: the promise constructor cannot be invoked directly

Error: the promise constructor cannot be invoked directly.

You can get this error for several reasons:

####1. You forgot to use new when creating a new promise using new Promise(resolver) syntax.

This can happen when you tried to do something like:

return Promise(function(resolve,reject){
       //...
})

You can correct this by doing:

return Promise(function(resolve,reject){
       //...
})

Please consider reading more about promisification and also consider checking out automatic promisification as well as Promise.method

####2. You are trying to subclass Promise

Bluebird does not support extending promises this way. Instead, see the Guide for Library Authors.