Javascript: String comparison returns true although the strings are different (intermittent issue)-CodePudding

I'm processing the data in chunks using WritableStream. The decoded data is a json string and in case it starts with , I need to remove the comma.

But here's the problem, after the chunk is being decoded to string I'm checking the first character

const startsWithComma = chunk.at(0) === ','

and SOMETIMES it returns true although the chunk doesn't start with , and causes the JSON.parse to fail later on. See the attached image.

Things I tried:

used .at() alternatives like .charAt(), .startsWith(), chunk[0]

The issue is intermittent meaning sometimes it can process the entire data and sometimes might fail mid through.

CodePudding user response：

so, expanding on my comment:

from your image, is it possible that the debug is running after the comma was already taken out? is it also possible that the chunk may begin with more than 1 comma so sometimes debugging at that exact spot would still show a comma?

The solution would be to take off the commas using a while loop such as

while( chunk.at(0)===',' ){
  chunk = chunk.slice(1).trim();
}

now I do not know the reason for doing it if isFirstChunk so I'd leave that alone, but the above loop should solve your startsWithComma issue :D