Request: Remove or make optional result property on output array

[BTMorton]

Currently, after doing an expansion, you attach the result object returned from the compiler on the array object. This then gets put into the cache object which takes up a significant amount of memory, particularly when the cache grows large, as it creates a new compiler for each call which is cached, leading to a ~5/6mb overhead every time.

This result property does not appear to be documented behaviour and after a quick github code search, I couldn't find any references to it. Could you either remove this property, make it an optional addition, or suggest a third option to help mitigate the memory usage?

I am currently using chokidar to watch media files for changes, on a folder with ~50k items in it. This leads to the cache object holding ~300mb of memory at ~60% of my total application's memory usage.

Example program to try to demonstrate the issue:

var chokidar = require('chokidar');
var braces = require('braces');

console.log("Test starting");
chokidar.watch('some/folder/with/many/files/*', {}).on('ready', (event, path) => {
  console.log("chokidar ready");

  if (global.gc) { global.gc(); }
  let memoryUsage = process.memoryUsage();
  console.log(`Before clear: ${memoryUsage.heapUsed}/${memoryUsage.heapTotal}`);

  braces.clearCache();

  if (global.gc) { global.gc(); }
  memoryUsage = process.memoryUsage();
  console.log(`After clear: ${memoryUsage.heapUsed}/${memoryUsage.heapTotal}`);

  process.exit();
});

Running the above using node --expose-gc bracesTest.js on my testing file system gives the following output:

Test starting
chokidar ready
Before clear: 446778640/585011200
After clear: 133833408/241065984

My testing system is created using symlinked media files into a single folder with the following script:

#!/bin/bash

for i in {0..50000} 
do
    ln -s ../MediaFile.mp4 clip_$i.mp4
done

Screenshot of the memory snapshot that led me to the cache:

Screenshot of the memory snapshot after adding a .slice() call to the memoize method when adding an item to the cache:

[jonschlinkert]

Thank you for taking the time to do this! I just made some major changes this past week that partially address this, but I will also go a step further and make sure that it's documented and that the object is only added if specified by the user for debugging.

[jonschlinkert]

done, braces was refactored and no extra properties are added to the result array.