Reconciling iteratee behaviour

[megawac]

I've been mostly silent on the merge but I think this is a great step forward. I would love to see a base platform which both underscore and lodash use. For this to work, strict semver will be a must going forward.

---

A major difference between underscore and lodash currently is how iteratees are created. As I assume this implementation will use iteratee in the same places both libraries currently do this may prove a major incompatibility.

For instance, lodash's iteratee has deep string support. Personally, I think this should be removed in v4 in favour of making the user explicitly request deep (e.g. _.map(obj, _.propertyDeep('a.b.c'))).

[jashkenas]

I would love to see a base platform which both underscore and lodash use.

To be clear, I'm hoping that instead of fragmentation, "Underdash 1.0" would be both "Lodash 4.0" and "Underscore 2.0". Otherwise, there's much less of a point.

Explicitly requesting deep path support seems wise.

[jridgewell]

I think deep support can be pretty easily integrated. Consider _.iteratee's "special" types:

• null and undefined returns _.identity
• function returns a bound (if necessary) function
• object returns a _.matcher function
• string returns a _.property function

Why not add array support for deep properties?

_.map(obj, ['a', 'b', 'c'])

[megawac]

I'm just not a big fan of how its currently handled in lodash (I'd prefer something more explicit like what you mentioned). I do not want to see us parsing strings (theres like 40 related issues in underscore).

[megawac]

"Underdash 1.0" would be both "Lodash 4.0" and "Underscore 2.0"

I think this is a good long term goal, but I expect for the merge to succeed we should start smaller. Both underscore and lodash have prominent identities in the JS community and currently have some ideological differences.

I see the starting point for this as making underdash the place to implement a core API for both libraries to share, and then have both libraries import (whether CJS/compilation/etc) the implementation herein this repo. Anyway, this conversation should probably moved to another thread (it was on gitter earlier https://gitter.im/jashkenas/underscore).

[jdalton]

Closed by #14.