[jQuery] val 메소드 getter, setter 구별법

결국 arguments의 length 속성을 이용한다.

val: function( value ) {

var hooks, ret, isFunction,

elem = this[0];

if ( !arguments.length ) {

if ( elem ) {

hooks = jQuery.valHooks[ elem.type ] || jQuery.valHooks[ elem.nodeName.toLowerCase() ];

if ( hooks && "get" in hooks && (ret = hooks.get( elem, "value" )) !== undefined ) {

return ret;

}

ret = elem.value;

return typeof ret === "string" ?

// handle most common string cases

ret.replace(rreturn, "") :

// handle cases where value is null/undef or number

ret == null ? "" : ret;

}

return;

}

isFunction = jQuery.isFunction( value );

return this.each(function( i ) {

var self = jQuery(this), val;

if ( this.nodeType !== 1 ) {

return;

}

if ( isFunction ) {

val = value.call( this, i, self.val() );

} else {

val = value;

}

// Treat null/undefined as ""; convert numbers to string

if ( val == null ) {

val = "";

} else if ( typeof val === "number" ) {

val += "";

} else if ( jQuery.isArray( val ) ) {

val = jQuery.map(val, function ( value ) {

return value == null ? "" : value + "";

});

}

hooks = jQuery.valHooks[ this.type ] || jQuery.valHooks[ this.nodeName.toLowerCase() ];

// If set returns undefined, fall back to normal setting

if ( !hooks || !("set" in hooks) || hooks.set( this, val, "value" ) === undefined ) {

this.value = val;

}

});

}