Fix issue with onDidChange not always being called

[nhevia]

Fixes #108 and fixes sindresorhus/electron-store#93

Adds a configuration option called watchFile.

Works exactly like watch but uses fs.watchFile instead of fs.watch, allowing the subscription to read changes in the file more than once.

useEffect(()=>{
    store.onDidChange('myKey', (newV, oldV) => {
      console.log(`Changed from ${oldV} to ${newV}`)
    })
},[])

Clearly slower (sometimes, benchmarking is unreliable 100/2000ms) than watch but the only way to truly watch a file in React (and possible other scenarios, but not tested).

[alifarooq0]

Great work @nhevia! Really need this to fix sindresorhus/electron-store#93. @sindresorhus can we please get this in ASAP?

[sindresorhus]

So fs.watch only fails on Ubuntu, right? Can't we just use fs.watchFile on Linux? No option needed.

[sindresorhus]

Also please open an issue on Node.js. I want to ensure the issue will be eventually fixed in Node.js.

[alifarooq0]

So fs.watch only fails on Ubuntu, right? Can't we just use fs.watchFile on Linux? No option needed.

I'm seeing #108 on macOS.

[sindresorhus]

I'm seeing #108 on macOS.

Ok, so let's use fs.watch on macOS too then.

[alifarooq0]

you mean fs.watchFile? Sure, works for me 👍 . @nhevia are you able to make the necessary changes? It will be a lot nicer to have this work without having to specify an extra option :).

[sindresorhus]

Yes

[nhevia]

Changes added.

Tests were failing, added to review.

[alifarooq0]

Wicked 👍

[alifarooq0]

Thanks for the quick turn around on this @nhevia!

[sindresorhus]

The PR title is outdated.

[alifarooq0]

Will you have time to address the feedback @nhevia?

[sindresorhus]

@nhevia Bump

[nhevia]

Tests passing. Feel free to squash this mess 👀