JSFiddle - React, Tailwind, and code Playground

by gaby de wilde

JavaScript

nums = new Set(['.','1','2','3','4','5','6','7','8','9','0']);
    hasOnlyNumbers = function(str){
      if(str.split('.').length > 2) { 
        return false 
      }
      if(str[0]=='-'){ 
        str = str.substring(1) 
      }
      return [...str].every(x=>nums.has(x));
    }

    alert(hasOnlyNumbers('-3243.234332'));
    alert(hasOnlyNumbers('-3243.234.3.32'));