Synta圎rror: cannot use `?` unparenthesized within `||` and `&` expressions.Synta圎rror: await is only valid in async functions, async generators and modules.Synta圎rror: applying the 'delete' operator to an unqualified name is deprecated.Synta圎rror: a declaration in the head of a for-of loop can't have an initializer.Synta圎rror: 'x' is a reserved identifier.Synta圎rror: 'use strict' not allowed in function with non-simple parameters.Synta圎rror: '0'-prefixed octal literals and octal escape seq.ReferenceError: reference to undefined property 'x'.ReferenceError: deprecated caller or arguments usage.

ReferenceError: can't access lexical declaration 'X' before initialization.ReferenceError: assignment to undeclared variable 'x'.RangeError: x can't be converted to BigInt because it isn't an integer.RangeError: repeat count must be non-negative.RangeError: repeat count must be less than infinity.RangeError: argument is not a valid code point.Error: Permission denied to access property 'x'.Enumerability and ownership of properties.

Javascript introduction for beginners