Design Meeting Notes, 8/12/2016 · Issue #10307 · microsoft/TypeScript

Map perf Optimize performance of maps (with ES3 support) #10298 / Optimize performance of maps #10270 Using Object.create(null) to produce maps increases overall perf ~15-20% and decreases memory ~20% Avoids calls to hasOwnProperty Breaks ES3 runtime use of tsc Force object into 'Dictionary' mode in V8 (by using delete operator) to get better perf Breaks compiler API Two possibilities Drop ES3 hos

[vvakame]

"👍 drop ES3 host support" とな。ええこっちゃ。