CODEWITHSUNDEEP
javascriptvisual-studio-code
Nagusameta
Nagusameta

Reputation: 99

Why do JavaScript errors seem to not get detected in Visual Studio Code console?

I'm new and learning from FreeCodeCamp, their editor runs the code below and displays " ReferenceError: sTr1 is not defined" screenshot here

However, with Visual Studio Code, and even here in stackoverflow, the code executes without a problem (screenshot from VSC).

I am curious why there is a difference. I also expect the error because of what I learned from another language (Java), that it cannot be used unless the variable was declared first. 

var str1 = "hi";
sTr1 = "hey";
console.log(sTr1);

Upvotes: 0

Views: 88

Answers (1)

connexo
connexo

Reputation: 56754

Assigning a value to a variable which hasn't been declared creates a global variable with that name automatically in non-strict mode, and throws a ReferenceError in strict mode.

Please note that ES modules are always in strict mode.

<script type="module">
  foo = "foo"; 
  console.log(foo); // ReferenceError: assignment to undeclared variable foo
</script>

<script>
  bar = "bar"; 
  console.log(bar); // "bar"
</script>

<script>
  "use strict";
  baz = "baz";
  console.log(baz); // ReferenceError: assignment to undeclared variable baz
</script>

Upvotes: 1

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