Throw error when passing invalid data to sharp()

[mikemorris]

Passing a raw image buffer JavaScript object to sharp() fails silently instead of throwing an error.

[lovell]

Hi Mike, input Buffer (and file) validation is "lazy" and occurs only when the toBuffer or toFile methods are called, or when data is first requested if using Streams.

I suspect the docs probably need to be a bit clearer about this behaviour.

Unless you've found a bug, which is entirely possible :)

[mikemorris]

Oops, turns out I was passing in an object instead of a buffer. In this case though, the callback below is never called, and no errors are thrown.

sharp({}).toBuffer(function(err, buffer, info) {
  console.log(err);
});

[lovell]

Ah ha, yes, the parameter-less constructor assumes you'll start to pipe the data in at some point, at which everything will come to life and, on completion, the callback function passed to toBuffer will be called.

The constructor logic could be tightened a little to throw an Error when something other than String or Buffer (or undefined) is provided. Leave it with me.

[lovell]

I've used your sharp({}) example, amongst others, to tighten this part of the API.

This is currently on the knife branch and will form part of v0.11.0. Thanks for the original suggestion.