UNRELEASED.md

Performance

• Optimize Hash#rehash for the common case, avoid calling $slice when no hash collision is present (#2571)

Fixed

• String#{r,l,}strip: Make them work like in MRI for non-breaking white-space (#2612)
• Compat regression fix: Hash#to_n should return a JS object (#2613)

Internal

• Bump the ECMA version from 3 to 12 for ESLint (#2537)