[IndexedDB] Syntax for opening a cursor

[Jeremy Orlow]

If I'm reading the current spec right (besides the "[NoInterfaceObject]"
attributes that I thought Nikunj was going to remove), if I want to open a
cursor, this is what I need to do:

myObjectStore.openCursor(new IDBKeyRange().leftBound("key"), new
IDBCursor().NEXT_NO_DUPLICATE);


Note that I'm creating 2 objects which get thrown away after using the
constructor and constant.  This seems pretty wasteful.

Jonas' proposal (which I guess Nikunj is currently in the middle of
implementing?) makes things a bit better:

myObjectStore.openCursor(window.indexedDB.makeLeftBoundedKeyRange("key"),
new IDBCursor().NEXT_NO_DUPLICATE);


or, when you have a single key that you're looking for, you can use the
short hand

myObjectStore.openCursor("key", new IDBCursor().PREV);


But even in these examples, we're creating a needless object.  I believe we
could also use the prototype to grab the constant, but the syntax is still
pretty verbose and horrid.

Can't we do better?

J

Re: [IndexedDB] Syntax for opening a cursor

[Tab Atkins Jr.]

On Thu, Jun 24, 2010 at 1:25 PM, Jeremy Orlow  wrote:
> If I'm reading the current spec right (besides the "[NoInterfaceObject]"
> attributes that I thought Nikunj was going to remove), if I want to open a
> cursor, this is what I need to do:
>
> myObjectStore.openCursor(new IDBKeyRange().leftBound("key"), new
> IDBCursor().NEXT_NO_DUPLICATE);
>
> Note that I'm creating 2 objects which get thrown away after using the
> constructor and constant.  This seems pretty wasteful.
> Jonas' proposal (which I guess Nikunj is currently in the middle of
> implementing?) makes things a bit better:
>
> myObjectStore.openCursor(window.indexedDB.makeLeftBoundedKeyRange("key"),
> new IDBCursor().NEXT_NO_DUPLICATE);
>
> or, when you have a single key that you're looking for, you can use the
> short hand
>
> myObjectStore.openCursor("key", new IDBCursor().PREV);
>
> But even in these examples, we're creating a needless object.  I believe we
> could also use the prototype to grab the constant, but the syntax is still
> pretty verbose and horrid.
> Can't we do better?

If we're specifying something that will get wrapped in a library to
make it less horrible *on day 1* (or earlier), we're doing it wrong.

All of the variants above are very, very wrong.

~TJ

Re: [IndexedDB] Syntax for opening a cursor

[Nikunj Mehta]

Hi Jeremy,

I have been able to push my changes (after more Mercurial server problems) just 
now. I reopened 9790 because Andrei's commit made IDBCursor and IDBObjectStore 
constants unavailable from the global object. After all this, you should be 
able to do the following for your need below:

myObjectStore.openCursor(IDBKeyRange.leftBound("key"), 
IDBCursor.NEXT_NO_DUPLICATE);

Nikunj
On Jun 25, 2010, at 4:25 AM, Jeremy Orlow wrote:

> If I'm reading the current spec right (besides the "[NoInterfaceObject]" 
> attributes that I thought Nikunj was going to remove), if I want to open a 
> cursor, this is what I need to do:
> 
> myObjectStore.openCursor(new IDBKeyRange().leftBound("key"), new 
> IDBCursor().NEXT_NO_DUPLICATE);
> 
> Note that I'm creating 2 objects which get thrown away after using the 
> constructor and constant.  This seems pretty wasteful.
> 
> Jonas' proposal (which I guess Nikunj is currently in the middle of 
> implementing?) makes things a bit better:
> 
> myObjectStore.openCursor(window.indexedDB.makeLeftBoundedKeyRange("key"), new 
> IDBCursor().NEXT_NO_DUPLICATE);
> 
> or, when you have a single key that you're looking for, you can use the short 
> hand
> 
> myObjectStore.openCursor("key", new IDBCursor().PREV);
> 
> But even in these examples, we're creating a needless object.  I believe we 
> could also use the prototype to grab the constant, but the syntax is still 
> pretty verbose and horrid.
> 
> Can't we do better?
> 
> J