How could I do it in Node.js to recognize if a string is a valid number?
Here are some examples of what I want:
"22" => true
"- 22" => true
"-22.23" => true
"22a" => false
"2a2" => false
"a22" => false
"22 asd" => false
I dont actually need to return "true" or "false", but I need an unequivocally way to distinguish them. It seems like isNaN isnt available in node.js...
isNaN() is definitely available in node.js.
!isNaN(+n)
The unary plus operator is my personal choice; won't catch your "- 22" example, but you could use !isNaN(+n.replace(/\s/g, "") to strip spaces.
+"" and +[] are 0. So this solution doesn't hold up under the very best garbage you throw at it.I use the method suggested in this answer:
function isNumber(n) {
return !isNaN(parseFloat(n)) && isFinite(n);
}
isNaN is not available in nodejsYou can use regexp for example :
function is_number(n) {
return (/^-?\d[0-9.e]*$/).test(n);
}
