Convert string to either integer or float in javascript

Question

Is there a straightforward way to parse a string to either integer or float if I don't know if the variable is integer-number-like or decimal-number-like?

a = '2'; // => parse to integer
b = '2.1'; // => parse to float
c = '2.0'; // => parse to float
d = 'text'; // => don't parse

EDIT: It seems my question lacked the necessary context: I want to do some calculations without losing the original format (Original format thereby means integer vs. float. I don't care about the original number of decimal places):

Example:

String containing the formatted number ('2') => parse to number (2.0) => do some calculations (2.0 + 1 = 3.0) => restore "original format" ('3' and not '3.0')

If the input was 2.0 instead, the wanted result would be '3.0' (not '3').

Answer 1

That's how I finally solved it. I didn't find any other solution than to add the variable type to the variable ...

var obj = {
	a: '2',
	b: '2.1',
	c: '2.0',
	d: 'text'
};
// Explicitly remember the variable type
for (key in obj) {
  var value = obj[key], type;
  if ( isNaN(value) || value === "" ) {
    type = "string";
  }
  else {
    if (value.indexOf(".") === -1) {
      type = "integer";
    }
    else {
      type = "float";
    }
    value = +value; // Convert string to number
  }
  obj[key] = {
    value: value,
    type: type
  };
}
document.write("<pre>" + JSON.stringify(obj, 0, 4) + "</pre>");