Added a compare function

[keeganstreet]

Comparing two selectors

Specificity Calculator now exposes a compare function. This function accepts two CSS selectors, a and b.

• It returns -1 if a has a lower specificity than b
• It returns 1 if a has a higher specificity than b
• It returns 0 if a has the same specificity than b

SPECIFICITY.compare('div', '.active');   // -1
SPECIFICITY.compare('#main', 'div');     // 1
SPECIFICITY.compare('span', 'div');      // 0

Ordering an array of selectors by specificity

You can pass the SPECIFICITY.compare function to Array.prototype.sort to sort an array of CSS selectors by specificity.