The MCP23017 is an I2C bus GPIO expander. This is an demonstration application for the ESP32 in the ESP-IDF environment.
To use this application, you must have the ESP-IDF environment installed. After cloning, you will need to run make menuconfig to set up the proper make files and then make flash to flash it onto your device.
Note: The MCP23017 component in this demonstration does not yet support interrupt functionality. Also, the intent isn't really to duplicate Arduino digitalWrite type functionality. After spending a little time with the datasheet and learning how to set and clear bits, you can easily accomplish what you need without trying to emulate Arduino.