`let` scope is not well supported

[tiancaiamao]

• Version: v9.3.0
• Platform: Linux genius 4.4.0-77-generic Updated README with less node.js-centric content, and more Node Forward. #98-Ubuntu SMP Wed Apr 26 08:34:02 UTC 2017 x86_64
• Subsystem: ES6 gramma

I'm new to node and javascript, I expect this code should work:

function test() {
    let TMP = false;
    (function() {
        let TMP = TMP || true;
    })();
}
test()

but when I run it, I get this error:

ReferenceError: TMP is not defined

[apapirovski]

You're redeclaring TMP in that scope which means you can't access the outside TMP anymore.

In general, this tracker is for issues or bugs in Node.js core. This question would be better suited to https://github.com/nodejs/help/issues.

@tiancaiamao

That is called temporal dead zone (TDZ). It's working per spec.

[tiancaiamao]

Thank you for point out that. @trvsapjiac