regex check if string contains no numbers code example

Example 1: check if string only contains integer digits numbers javascript

let val = '1234567890' 
let isnum = /^\d+$/.test(val);
if (isnum) {
  // val is a number
}

Example 2: regex all not numbers

echo 1a2b3c | sed 's/[^0-9]//g'	#Replaces all not numbers
abc