Contains nodes for working with an SD card on ESP32, also for the example I added nodes for working with a string.
In order for the SD card to be initialized and opened, it must be formatted as FAT16 or FAT32 (if it works with arduino, then everything is fine). IT IS IMPORTANT THAT THE FILE NAME MUST BEGIN WITH "/". OTHERWISE OPENING OR CREATING A FILE WILL BE A NODE ERROR. The example was tested on a regular ESP32. SPI PINS (MOSI -GPIO23, MISO - GPIO19, SCK - GPIO18) ARE INDICATED IN THE CODE. ESP32 MODELS OF DIFFERENT TYPES NEED TO BE SPECIFIED WITH THE DOCUMENTATION!!!