split IDBCursor direction into isForward and isDuplicative

[DartBot]

This issue was originally filed by @seaneagan

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In IDBCursor, I think this...

static final int NEXT = 0;
static final int NEXT_NO_DUPLICATE = 1;
static final int PREV = 2;
static final int PREV_NO_DUPLICATE = 3;

final int direction;

...should be replaced by:

final bool isForward;
final bool isDuplicative;

and then in IDBIndex and IDBObjectStore:

IDBRequest openCursor([IDBKeyRange range, bool isForward = true, isDuplicative = true]);
IDBRequest openKeyCursor([IDBKeyRange range, bool isForward = true, isDuplicative = true]);

[madsager]

Added Area-DOM, Triaged labels.

[rakudrama]

These constants have been replaced by strings in the latest spec: http://www.w3.org/TR/IndexedDB/#dfn-direction

"next", "nextunique", "prev" and "prevunique".

[rakudrama]

Passing booleans is not great API design. It is better to have an enum
(direction: FORWARD, direction: BACKWARD) rather than (isForward: true, isForward: false).

I would prefer to get some more experience with the API before deciding on whether separating direction from unique keys is helpful.

I'm going to leave this aligned with the DOM IDL, at least until Dart gets proper enums.

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Added this to the Later milestone.
Removed Type-Defect label.
Added Type-Enhancement, WontFix labels.

[DartBot]

This comment was originally written by edouardtavi...@gmail.com

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Hi! Could you add the strings to some constant fields in dart:indexeddb Cursor? Twould be great :)