joint.all.js
function(args) {

                var amount = _.isFinite(args.amount) ? args.amount : 1;

                return _.template('<filter><feColorMatrix type="saturate" values="${amount}"/></filter>', {
                    amount: 1 - amount
                });
            }
function(args) {

                var amount = _.isFinite(args.amount) ? args.amount : 1;

                return _.template('<filter><feColorMatrix type="saturate" values="${amount}"/></filter>', {
                    amount: 1 - amount
                });
            }
`amount` ... the proportion of the conversion. A value of 0 is completely un-saturated. A value of 1 leaves the input unchanged.