Suggest language when one isn't found

[stevenzeck]

Closes #115

• Suggests a language if the provided language -l is not found

[Glavin001]

I would be OK if you also wanted to add https://www.npmjs.com/package/fast-levenshtein

cc @lassik @muuvmuuv

Something like:

const languages = getAllLanguages();

const distances: number[] = languages.map(lang =>
  levenshtein.get(lang.toLowerCase(), language.toLowerCase())
);
const bestDistance: number = Math.min(...distances);

const bestMatchLanguages = getAllLanguages().filter((lang, index) =>
  distances[index] === bestDistance
);

// ...

const error = new Error(
  `Language '${language}' was not found. Did you mean '${bestMatchLanguages.join(" or ")}'?`
);

The above only gets the best. It could also be modified to support an arbitrary threshold:

- distances[index] === bestDistance
+ const distanceThreshold = 2;
+ distances[index] <= (bestDistance + distanceThreshold)

So C would also show C++ and visa versa 😉 .

[Glavin001]

I think this should be return Promise.resolve(); and the method return type is : Promise<void>

[Glavin001]

We should probably limit the number of matches returned, just in case.

const limit = 3;
bestMatchLanguages.slice(0, limit).map(lang => `- ${lang}`).join("\n")

[Glavin001]

I don't think I like the double \n here.

I just noticed the snapshot at https://github.com/Unibeautify/unibeautify-cli/pull/116/files#diff-79f3cbac345f885b9f1a9467fa09ae86R55

Suggested change

	`Language '${language}' was not found. Did you mean:\n\n${bestMatchLanguages
	`Language '${language}' was not found. Did you mean:\n${bestMatchLanguages

[Glavin001]

One thing I like to do is indent list items to the console.

Suggested change

	.map(lang => `- ${lang}`)
	.map(lang => ` - ${lang}`)

[Glavin001]

@stevenzeck I think this is getting really close. Awesome work! I'm really excited to merge this 😃