$-resolve.js

$.resolve = function(arg) {
    var args = arguments,
        sliceDeferred = [].slice,
        i = 0,
        length = args.length,
        count = length,
        rejected,
        deferred = length <= 1 && arg && jQuery.isFunction(arg.promise) ? arg : jQuery.Deferred();
    
    function resolveFunction(i, reject) {
        return function( value ) {
            rejected = true;
            args[ i ] = arguments.length > 1 ? sliceDeferred.call(arguments, 0) : value;
            if ( !( --count ) ) {
                // Strange bug in FF4:
                // Values changed onto the arguments object sometimes end up as undefined values
                // outside the $.when method. Cloning the object into a fresh array solves the issue
                var fn = rejected ? deferred.rejectWith : deferred.resolveWith;
                fn.call(deferred, deferred, sliceDeferred.call(args, 0));
            }
        };
    }
    
    if (length > 1) {
        for( ; i < length; i++) {
            if (args[ i ] && jQuery.isFunction(args[ i ].promise)) {
                args[ i ].promise().then(resolveFunction(i), resolveFunction(i, true));
            } else {
                --count;
            }
        }
        if (!count) {
            deferred.resolveWith(deferred, args);
        }
    } else if (deferred !== arg) {
        deferred.resolveWith( deferred, length ? [ arg ] : [] );
    }

    return deferred.promise();
};