Summary for the 66th meeting of Ecma TC39 Ecma Technical Committee 39 held three day meeting hosted by Paypal in NYC on September 25th - September 27th, 2018. Agenda can be found here. New Proposals TC39 discussed 6 new proposals. 5 entered staging process to discuss towards specification, and 1 remains at Stage 0 for further investigation before consensus. Advanced to Stage 1 for-in mechanics Uni