Handing errors

[shiffman]

Thanks also to @dariusk I'm writing this issue to open a discussion about error handling. We should develop a plan and style guide for handling errors. At a minimum we should have custom console.logs to give users information about errors, but we should likely use some sort of try, catch, throw magic.

A good example scenario as demonstrated by @dariusk is the following:

let average = wordVectors.average(['red', 'askdjfkjalksdjf'], 1); 

Right now the error produced is a lot of NDArray garble and we should alert the user that askdjfkjalksdjf is not a word in the word2vec dictionary.

[shiffman]

Oops, I forgot I opened #65 already! Will keep this issue in lieu of that one, but will note here that another scenario is trying to use a model before it is loaded!

[cvalenzuela]

This has been addressed in the new source code. Each file and case is different but we have tried to create helpful error messages whenever possible. Some references:

• https://github.com/ml5js/ml5-library/blob/master/src/ImageClassifier/index.js#L110
• https://github.com/ml5js/ml5-library/blob/master/src/PitchDetection/index.js#L126
• https://github.com/ml5js/ml5-library/blob/master/src/FeatureExtractor/index.js#L33
• https://github.com/ml5js/ml5-library/blob/master/src/FeatureExtractor/Mobilenet.js#L154
• https://github.com/ml5js/ml5-library/blob/master/src/FeatureExtractor/Mobilenet.js#L203
• https://github.com/ml5js/ml5-library/blob/master/src/PitchDetection/index.js#L32
• https://github.com/ml5js/ml5-library/blob/master/src/PitchDetection/index.js#L35
• https://github.com/ml5js/ml5-library/blob/master/src/PitchDetection/index.js#L120
• https://github.com/ml5js/ml5-library/blob/master/src/PitchDetection/index.js#L126

I'm closing this for now since this issue already influenced a lot in the src code, and I think it might be better to open individual issues for specific cases.

[shiffman]

Amazing work, thank you @cvalenzuela!