ArduinoJsonI2CEepromReader.h

#include <stdlib.h>
#include <stddef.h>
#include "Arduino.h"
#include "SparkFun_External_EEPROM.h"
#include <ArduinoJson.h>

struct EepromJsonReader {

    uint16_t pos = 0;
    ExternalEEPROM reader = ExternalEEPROM();

    uint8_t address = 0x50;

    EepromJsonReader(uint8_t addy=0x50) {
        pos = 0;
        address = addy;
        Wire.begin();
        reader.begin(addy);
        Wire.setClock(1000000);
    }
    // Reads one byte, or returns -1
    int read() {
        Serial.println(pos);
        char val = reader.read(pos);
        pos++;
        return val;
    }
    // Reads several bytes, returns the number of bytes read.
    size_t readBytes(uint8_t* buffer, size_t length) {
        
        reader.read(pos, buffer, length);
        pos = pos + length;
        
        return length;
    }
};
 
class EepromJson {

  private:
    uint8_t address = 0x50;
    
    
  public:
  
    StaticJsonDocument<1000> json;
    EepromJsonReader ejr; 

    EepromJson(uint8_t addy=0x50) {
        address = addy;

    }
    void begin() {
        ejr = EepromJsonReader(address);
        DeserializationError error = deserializeJson(json, ejr);
    }
};


EepromJson eeprom(0x50);

void setup() {
  eeprom.begin();
}

void loop() {
  Serial.println(eeprom.json["myKey"]);
}