Chrome console already declared variables throw undefined reference errors for let

This happens when you introduce the temporal dead zone to the global scope. As you might know, let declarations are hoisted but left uninitialised. Due to control flow, it can happen that a variable is never initialised: function …() { if (false) example; // would throw a ReferenceError if it was evaluated … // do … Read more

Value of “this” is incorrect when debugging Babel transpiled React with Chrome Devtools

Unfortunately this is a fact of life when using the debugger in Babelified code with Chrome. To implement arrow functions with the ECMAScript spec behavior, the this keyword needs to be transformed into a different name, and there’s currently no way to tell Chrome what do to for debugging. Firefox’s developer tools have a bunch … Read more