writing numbers and strings to a file in node.js

Question

I've got a node.js app where I'm trying to read and write numbers and stings to files.

I'm currently writing

fs.writeFileSync(myPath, value);

where value can be either a number or a string.

When I read the file

fs.readFileSync(myPath,'utf-8');

I get the file as a string. I'm hoping there is a way for me to read the file, without needing to specify if the contents of the file are a number or a string. Is this possible?

The way around it, I suspect, is to try to convert the string to a number and see if it fails, but I'm hoping there is a better way. I'm happy to use fs.writeStream/fs.readStream with buffers (actually preferrable), but I'm not sure exactly what the best path here is.

adeneo · Accepted Answer · 2014-04-06 01:43:25Z

1

When the encoding option is specified then readFileSync returns a string.
Otherwise it returns a buffer.

So say the docs

To read a buffer you'd normally use .toString('utf8') in Node, so that gets you nowhere.
In other words, reading a file will return a string in Node, and not a valid integer, but you can check if the string is a number, it's as easy as calling isNaN

var is_number = !isNaN(file_string);

answered Apr 6, 2014 at 1:43

adeneo

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2 Comments

pedalpete Over a year ago

I was hoping there would be something nicer, but I could do return isNaN(file_output) ? file_output : parseInt(file_output)

adeneo Over a year ago

Yes you could, remember the radix in parseInt!

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