Im receiving some file chunks in bytes format from my server and im collecting them into one variable in my frontend to download it later. And I can't change my server conception (receiving a file sliced into chunks).
My problem is that if the file is heavy (from 500MB), my variable length is starting to be very very big and im having an error :
RangeError: Invalid string length
This is because my variable has reach the limit of character (536 800 000).
Here's how im adding my data to my variable :
this.socket.on('new_file', (data: string) => {
this.receivedFile += data;
}
My download part :
public download(): void {
const byteCharacters = this.receivedFile;
const byteArrays = [];
const sliceSize=512
for (let offset = 0; offset < byteCharacters.length; offset +=
sliceSize) {
const slice = byteCharacters.slice(offset, offset + sliceSize);
const byteNumbers = new Array(slice.length);
for (let i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
const byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
const blob = new Blob(byteArrays, {type: this.fileInfos.type});
saveAs(blob, this.fileInfos.name);
}
Which approach can I do ? Or does it exist some variable type in Javascript to accept more char ? Thanks
Don't collect the chunks into a huge string. Instead, just convert each chunk into a bytearray immediately (that you'll need later anyway) and collect these:
this.socket.on('new_file', (data: string) => {
const bytes = new Uint8Array(data.length);
for (let i = 0; i < data.length; i++) {
bytes[i] = data.charCodeAt(i);
}
this.byteArrays.push(bytes);
}
then
public download(): void {
const blob = new Blob(this.byteArrays, {type: this.fileInfos.type});
saveAs(blob, this.fileInfos.name);
}
I don't think you need to make 512-byte-sized slices.
Does stringifying one character at a time and then concatenating the result work?
e.g.
var out="[";
for(var indx=0;indx<data.length-1;indx++){
out+=JSON.stringify(data[indx],null,4)+",";
}
out+=JSON.stringify(data[data.length-1],null,4)+"]";
Credit: https://dev.to/madhunimmo/json-stringify-rangeerror-invalid-string-length-3977