Provide a false value instead of undefined

[giorgio79]

For removed, or added values instead of false an undefined is provided.

Would be nice to provide false instead of undefined.

{ a: 'On the other hand , I love you .',
  b: 'Because , I love you .' }
[ { count: 4,
    added: undefined,
    removed: true,
    value: [ 'On', 'the', 'other', 'hand' ] },
  { count: 1,
    added: true,
    removed: undefined,
    value: [ 'Because' ] },
  { count: 5, value: [ ',', 'I', 'love', 'you', '.' ] } ]

[ExplodingCabbage]

I think I agree. Especially for TypeScript users (currently using the third-party type definitions from DefinitelyTyped), it'd be nice to have consistent types and not have to puzzle over whether there's a semantic distinction between removed: false and removed: undefined. The single downside I see to this change is that it'll mean serializing a patch object to JSON with JSON.stringify (which simply omits properties whose value is undefined) will produce slightly larger objects, potentially harming performance for anyone who's using jsdiff serverside and emitting diffs to a client as JSON. For that reason I think it makes sense to do this but treat it as a breaking change.