how i check during slightest twin subexpressions unchanging countenance match?

i am perplexing review floating-point decimal numbers unchanging expression. there competence may array before decimal, decimal competence may present, donation competence may have digits after it. (for application, streamer +/- trailing "e123" allowed). i have combined regex:

/^([\d]*)(\.([\d]*))?$/

which justly matches following:

1
1.
1.23
.23

however, also matches lifeless twine string only decimal point, i want.

currently i am checking after controlling regex $1 $3 length incomparable 0. not, valid. there proceed i directly regex?