Add _.sortByDescending function

[mareek]

Add a function to do a stable sorting in reverse order since there is currently no way to this in underscore (_sortBy().reverse() change the order of equal elements).

sortBy has been refactored so that sortBy and sortByDescending share most of their implementation

[bjmiller]

I suspect that this will be turned down out-of-hand anyway, but... Would it make more sense to pass an options hash along with plain old sortBy, like {sort: 'descending'}?

[mareek]

@bjmiller Adding another parameter to sortBy would break existing code (see PR #920 ).

[bjmiller]

Well, let's not do that, then. It was worth a thought.

[jashkenas]

For descending sorts, if you don't want to have to reverse — I think that passing an iteratee function is a fine approach. No need for an additional option or separate function.

[mareek]

I don't see how I can sort on a string property in reverse order by using iteratee function. can you give me an example, please ?

[jashkenas]

Of course — you're quite right – I was thinking of using a regular .sort() for this case.

[mareek]

Unfortunately .sort() isn't stable on every browser when sorting big arrays (I'm looking at you, chrome) so using .sort() won't solve the problem.

[mareek]

Besides, adding a proper way to sort by descending order would make sort chaining scenario much simpler (instead of relying on tricks like this)

[megawac]

I think this could be useful but should wait for #1768 and #1751 are resolved