src/js/hammer.js
function boolOrFn(val, args) {
    if (typeof val == TYPE_FUNCTION) {
        return val.apply(args ? args[0] || undefined : undefined, args);
    }
    return val;
}
function boolOrFn(val, args) {
    if (typeof val == TYPE_FUNCTION) {
        return val.apply(args ? args[0] || undefined : undefined, args);
    }
    return val;
}
function boolOrFn ( val , args ) { if ( typeof val == TYPE_FUNCTION ) { return val . apply ( args ? args [ 0 ] || undefined : undefined , args ) ; } return val ; }
let a boolean value also be a function that must return a boolean
this first item in args will be used as the context
@param {Boolean|Function} val
@param {Array} [args]
@returns {Boolean}
let a boolean value also be a function that must return a boolean this first item in args will be used as the context