How to Determine if a JavaScript Variable Holds an Integer Value?

How Do I Check if a Variable Is an Integer in JavaScript?

Validating the integer nature of a variable in JavaScript is crucial. To accomplish this, consider the following:

Do You Consider Strings as Potential Integers?

If so, this function will suffice:

<code class="javascript">function isInt(value) {
  return !isNaN(value) &amp;&amp; parseInt(Number(value)) == value &amp;&amp; !isNaN(parseInt(value, 10));
}</code>

Bitwise Operations for Integer Validation

If not, these alternative methods provide efficient solutions:

Simple Parsing and Checking

<code class="javascript">function isInt(value) {
  var x = parseFloat(value);
  return !isNaN(value) &amp;&amp; (x | 0) === x;
}</code>

Short-Circuiting and Parse Optimization

<code class="javascript">function isInt(value) {
  if (isNaN(value)) {
    return false;
  }
  var x = parseFloat(value);
  return (x | 0) === x;
}</code>

All in One Shot

<code class="javascript">function isInt(value) {
  return !isNaN(value) &amp;&amp; (function(x) { return (x | 0) === x; })(parseFloat(value))
}</code>

Performance Considerations

Benchmarking reveals that the short-circuiting solution offers the best performance (ops/sec).

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