jQuery version compatibility detection

Question

Are there any resources that can test a jQuery script/extension/plugin/whatever for version compatibility issues?

Answer 1

Here's my quick and dirty solution:

var versionGTE = function (valueA, valueB) {
  var values = [valueA, valueB];
  values.sort();
  // if valueA > valueB, values will have switched
  return (values[1] === valueA);
};

Example usage:

if (versionGTE(jQuery.fn.jquery, "1.3")) {
  // don't use @ in attr selectors
}

It does an alphabetical sort on the array. The only time it fails is if for some reason the version "x.y" vs "x.y.0". In that case the .0 version is perceived as being greater. It doesn't support "pre" versions either.

Here's a smaller version:

var versionGTE = function (valueA, valueB) {
  return ([valueA, valueB].sort()[1] === valueA);
};

Here's a more reliable function if you're worried about "rc1", "pre", or x.0 versions:

var versionCompare = function (versionStringA, versionStringB) {
  // quick test of equality before digging in
  if (versionStringA === versionStringB) return 0;

  var versionedAlpha = /[a-z]+(\d+)/gi,
      getArray = function (verString) {
        // replace rc1, rc2, beta3, etc with .-1.1, .-1.2, .-1.3, etc
        return verString.replace(versionedAlpha, ".-1.$1").split(".");
      },
      valuesA = getArray(versionStringA),
      valuesB = getArray(versionStringB),
      maxLength = Math.max(valuesA.length, valuesB.length),
      hasLetters = /[a-z]/gi,
      // assume any version with letters is -1 (pre, rc, etc)
      // also assume that any null entries are 0 (1.5 === 1.5.0)
      parseVersion = function (verString) {
        return (verString) ? (hasLetters.test(verString)) ? -1 : parseInt(verString, 10) : 0;
      };

  // verify both arrays are the same size
  valuesA.length = maxLength;
  valuesB.length = maxLength;

  for (var i = 0; i < maxLength; i++) {
    var valueA = parseVersion(valuesA[i]),
        valueB = parseVersion(valuesB[i]);

    if (valueA < valueB) {
      return -1;
    } else if (valueA > valueB) {
      return 1;
    }
  }

  // all equal at this point
  return 0;
};

This is like a sort or .compare function in that it will return 0 if equal, 1 if a > b, and -1 if a < b. Example:

if (versionCompare(jQuery.fn.jquery, "1.3") >= 0) {
  // don't use @ in attr selectors
}