How to identify if first character in a string is a number in Javascript

Question

When given a string such as

address = "12345 White House Lane"

Is there any way to identify whether the first character of the string ("1" in the example above) is a number or a character? In my case I need to be able to identify if its a number, and if so, shave off the number part of the address (leaving only the street name).

I have tried using the isNaN function

if(isNaN(address[0]){
    //Do this or that
}

but I am told that it is not reliable enough for broad using. Was also told that I could use a regex function similar to

if(address.matches("[0-9].*")){
    //Do this or that
}

But that only seems to throw type errors that I dont fully understand.

word.match(/[0-9].*/) <- there is no matches, and you want a regex literal, not a string — Jonas Wilms
– Jonas Wilms, Commented Apr 16, 2018 at 13:58

Nina Scholz · Accepted Answer · 2018-04-16 13:58:55Z

5

You could remove it with a regular expression which looks for starting digits and possible whitespace.

var address = "12345 White House Lane";

address = address.replace(/^\d+\s*/, '');
console.log(address);

answered Apr 16, 2018 at 13:58

Nina Scholz

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Scott Sauyet · Accepted Answer · 2018-04-16 14:12:53Z

0

You could split it into the two recognized parts with a function like this:

const splitAddress = address => {
  let {1: number, 2: street} = address.match(/^\s*(\d*)\s*(.+)/)
  return {number, street}
}

console.log(splitAddress('12345 Main St')) //=> {"number": "12345", "street": "Main St"}
console.log(splitAddress('Main St')) //=> {"number": "", "street": "Main St"}
console.log(splitAddress('219 W 48th St')) //=> {"number": "219", "street": "W 48th St"}

answered Apr 16, 2018 at 14:12

Scott Sauyet

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