Javascript auto inference using .toString() [duplicate]

Question

This question already has answers here:

Calling member function of number literal (3 answers)

1.toString() SyntaxError in Javascript (4 answers)

Closed 9 years ago.

Why doing this

123.toString()

gives an error...

but this

(123).toString()

Works OK

if possible and "at low level" answer (JIT/Interpreter parsing tokens decisions)

Answer 1

The JavaScript interpreter considers the . to be a decimal point, and therefore does not expect an alphabet character to follow it, hence the "unexpected token" error. Putting 123 in parentheses tells the interpreter, "run toString() on this object."