JavaScript/Notes/ParameterObject: Difference between revisions
No edit summary |
No edit summary |
||
| Line 23: | Line 23: | ||
Like this: | Like this: | ||
<source lang="javascript"> | <source lang="javascript"> | ||
Action.touchstart( document.body, {clientX: 330, clientY: 330} ); | |||
</source> | </source> | ||
Where <code>options</code> has a corresponding property for each argument. | Where <code>options</code> has a corresponding property for each argument. | ||
See also [http://c2.com/cgi/wiki?TooManyParameters Too Many Parameters]. | See also [http://c2.com/cgi/wiki?TooManyParameters Too Many Parameters]. | ||
Revision as of 09:39, 30 November 2013
Passing around lists of parameters? Typechecking arguments? Stop doing that. Here's how to make your code clearer and less error-prone.
The DOM event methods for creating events are an example of what not to do. My comments on w3c DOM mailing list led to the current Event constructor.
Method initTouchEvent (Apple) is fine example of terrible design. Here's how to change that.
<source lang="javascript">
var touchEvent, canceled;
touchEvent = doc.createEvent("TouchEvent"); if (typeof touchEvent.initTouchEvent == "function") {
touchEvent.initTouchEvent(type, bubbles, cancelable, view, detail, screenX, screenY, pageX, pageY, ctrlKey, altKey, shiftKey, metaKey, touches, targetTouches, changedTouches, scale, rotation);
// fire the event canceled = target.dispatchEvent(touchEvent);
} </source> 18 parameter variables is too many. Instead, we can pass in an object.
Like this:
<source lang="javascript">
Action.touchstart( document.body, {clientX: 330, clientY: 330} );
</source>
Where options has a corresponding property for each argument.
See also Too Many Parameters.