Large file sending by using react-native-ble-plx

I'm trying to write in a characteristic that sends a binary file as the value, this value is large, it's 19215 bytes which is not a problem because i've divided the file into 240 bytes for each element and each time encode the element to base64 and i use the function writeCharacteristicWithResponseForDevice() in order to write that element,

the issue is i successfully wrote the whole file 19215 bytes using a loop to write each time an element, but while i tried to read the characteristic i can only read the last written element

Example:

           this.manager.writeCharacteristicWithResponseForDevice(device.id,"1111", "40E1ED56-EC4A-4DC6-A6BD-30377F186B77", base64.encode(element1)           this.manager.writeCharacteristicWithResponseForDevice(device.id,"1111", "40E1ED56-EC4A-4DC6-A6BD-30377F186B77", base64.encode(element2))            this.manager.writeCharacteristicWithResponseForDevice(device.id,"1111", "40E1ED56-EC4A-4DC6-A6BD-30377F186B77", base64.encode(element3))

when i read the Characteristic using

          device.readCharacteristicForService("1111", "40E1ED56-EC4A-4DC6-A6BD-30377F186B77")

i get as a value :

        console.log(base64.decode(characteristic.value) => element3

it should be element1+ element2 + element3

-

here is my code for writing :

  WriteIncaracteristic() {   // this.state.fileSize is calculated in another function      const nbPackages = Math.floor(this.state.fileSize/240) + 1      var fileArray = []     for (let i = 0; i <= nbPackages; i++) {      // this.state.fileContent is created in another function      fileArray.push(this.state.fileContent.slice(0, 240))      this.state.fileContent = this.Remove(this.state.fileContent, 0, 240)     }     for (let j = 0; j <= fileArray.length; j++) {       if (fileArray[j]) {       const device = this.state.myDevice           this.manager.writeCharacteristicWithResponseForDevice(device.id,"1111","40E1ED56-EC4A-4DC6-A6BD-30377F186B77", base64.encode(fileArray[j]))            .then((characteristic) => {              console.log(base64.decode(characteristic.value));              return             }) .catch((error) => {              this.createTAlert("writing", error.message  )            });     }}  }

here is the function to read characteristic:

     ReadCaracteristic() {          const device = this.state.myDevice          device.readCharacteristicForService("1111", "40E1ED56-EC4A-4DC6-A6BD-30377F186B77")          .then((characteristic) => {               console.log(base64.decode(characteristic.value));               console.log(characteristic );            return            }) .catch((error) => {               // Handle errors               this.createTAlert("Reading", error.message  )           });

}

Can anybody help please by providing a working example in how to send large package files, because the problem can be while writing, the function erases the older value maybe.

Thanks