Node.js how to read and write arrays to file as binary - arrays

Question

I have a big array that I need to read in from a file. Normally I would save it as JSON, but the size of the UTF-8 encoded file is substantially larger and I have very strict size requirements so every Kb is precious.
Here's what I have so far:
// https://www.npmjs.com/package/typedarray-to-buffer
var toBuffer = require('typedarray-to-buffer');
var buffer = toBuffer(myArray);
var wstream = fs.createWriteStream('./myArray');
wstream.write(buffer);
// later...
var buff = new Buffer(data); // <-- file data passed in as a buffer
myArray = buff; // <--still binary :-(
I'm following this helpful article about writing binary files but it doesn't cover how to read them back in. I think the part I'm stuck in is turning the buffer data back into an array.
Update
Here's the console.log() for the array before it's written to file:
Int32Array {
'0': 2107281600,
'1': -370226405,
'2': 274543611,
'3': 172775319,
'4': -1927927544,
'5': -248215383,
'6': -1295527238,
'7': -1774538531,
'8': -784581845,
'9': 651425656,
'10': -534521241,
'11': -1788883022,
'12': 1679049410,
'13': -1728518340,
...

Answer 1

It is actually very simple to write binary to file. Use the "binary" encoding type string for the writeFileSync method from FS. Like so :
// Assume you have an Int32Array called myArray
var fs = require('fs');
fs.writeFileSync('/tmp/test.bin', myArray, 'binary');
Now you can check that the size of the file matches the byte size of the typed array. For example, myArray.length*4 will be the size of your data which in my case is 1228624. The file system says :
$ ls -l /tmp/test.bin
-rw-rw-r-- 1 flatmax flatmax 1228624 May 5 17:58 /tmp/test.bin