immutable-js/immutable-js 2.1.0

on GitHub

New:

• Indexed Sequences are now always treated densely, including Vector and ArraySequence. This means iterators, forEach, and Sequence methods visit unset indices, and has returns true for unset indicies within length. This warrants a minor-version bump.
• flatten turns a Sequence of Sequences into a single Sequence.
• flatMap maps over a Sequence, flattening the result. The alias chain is provided to begin to adhere to the Fantasy Land spec.
• Indexed Sequences can now be accessed by negative indicies, which index from the end of the Sequence.

Bugs:

• ensure 3rd argument in sequence functions is always parent sequence.
• reduce behavior matches Array#reduce.
• join behavior matches Array#join
• Fix type definition error for mergeDeep
• Fix equality checking for Sets.
• Fix issue where Safari/JSC incorrectly JITs hash creation, resulting in "missing values" or exceptions.