Did you notice that "let" is coming in through ecmascript? https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let https://developer.m

Did you notice that "let" is coming in through ecmascript? https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...