Error heroku deploy "not support platform undefined"

[alfaben12]

Error: say.export(): does not support platform undefined

how to fix this problem?

[tlhunter]

The say.export() method is not supported on Linux, which is what Heroku runs your code on:
https://github.com/Marak/say.js#feature-matrix

To get this to work someone will need to add support for exporting audio on Linux.

You did find a bug though in that this.platform is not being set:

say.js/platform/linux.js

Line 33 in 2d83f23

throw new Error(`say.export(): does not support platform ${this.platform}`)