lanying@lanyingdeMacBook-Pro _not-business % yarn global add es-checker yarn global v1.22.11 [1/4] 🔍 Resolving packages... [2/4] 🚚 Fetching packages... [3/4] 🔗 Linking dependencies... warning " > ts-node@10.2.1" has unmet peer dependency "@types/node@*". [4/4] 🔨 Building fresh packages...
success Installed "es-checker@1.4.2" with binaries: - es-checker ✨ Done in 2.37s. lanying@lanyingdeMacBook-Pro _not-business % es-checker
ECMAScript 6 Feature Detection (v1.4.2)
Variables √ let and const √ TDZ error for too-early access of let or const declarations √ Redefinition of const declarations not allowed √ destructuring assignments/declarations for arrays and objects √ ... operator
Data Types √ For...of loop √ Map, Set, WeakMap, WeakSet √ Symbol √ Symbols cannot be implicitly coerced