Bug: Aigle tries to call then even if it's not a function

[adrian-gierakowski]

This is different to the behaviour of native nodejs Promise (which only treats a value as a promise if then is a function):

> node --eval 'Promise.resolve({ then: 1 }).then(x => console.log(x))'
{ then: 1 }

Aigle:

> node --eval 'require("aigle").resolve({ then: 1 }).then(x => console.log(x))'
/Users/adrian/aigle-test/node_modules/aigle/lib/internal/util.js:169
  promise.then(resolve, reject);
          ^

TypeError: promise.then is not a function
    at callThen (/Users/adrian/aigle-test/node_modules/aigle/lib/internal/util.js:169:11)
    at callReceiver (/Users/adrian/aigle-test/node_modules/aigle/lib/internal/util.js:165:3)
    at Function._resolve [as resolve] (/Users/adrian/aigle-test/node_modules/aigle/lib/aigle.js:3746:3)
    at [eval]:1:18
    at Script.runInThisContext (vm.js:120:20)
    at Object.runInThisContext (vm.js:311:38)
    at Object.<anonymous> ([eval]-wrapper:10:26)
    at Module._compile (internal/modules/cjs/loader.js:1138:30)
    at evalScript (internal/process/execution.js:94:25)
    at internal/main/eval_string.js:23:3

Tested with:

> node --version
v12.18.2

[suguru03]

Hi @adrian-gierakowski !
Thanks for reporting the issue and catching the bug!

We need to check this condition strictly. ✍️
https://github.com/suguru03/aigle/blob/master/lib/internal/util.js#L147

I welcome your PR 😄