Collection.offset() - zuki/Dexie.js GitHub Wiki

Syntax

collection.offset(count)

Parameters

count: Number	Number of entries to skip. Must be >= 0.

Return Value

This Collection instance (this)

Remarks

Skips the first N entries from the resulting Collection. In case skipping the last N entries is requested, this method can be used in combination with the Collection.reverse() method.

Sample

This sample will sort friends by lastName and include the last 15th to 10th friend.

db.friends.orderBy('lastName').reverse().offset(10).limit(5);

Limitations

In combination with the or() method, the offset() method makes no sense since the sort order of the result will be undefined (or() is working on multuple different indexes in parallell). Instead, use sortBy() and then slice the resulting array from requested offset.

Performance Notes

If executed on simple queries, the native IDBCursor.advance() method will be used (fast execution). If advanced queries are used, the implementation have to execute a query to iterate all items and ignore N items using a JS filter.

Examples where offset() will be fast

db.[table].offset(N)
db.[table].where(index).equals(value).offset(N)
db.[table].where(index).above(value).offset(N)
db.[table].where(index).below(value).offset(N)
db.[table].where(index).between(value).offset(N)
db.[table].where(index).startsWith(value).offset(N)

Examples where offset() will have to iterate the collection:

db.[table].where(index).equalsIgnoreCase(value).offset(N)
db.[table].where(index).startsWithIgnoreCase(value).offset(N)
db.[table].where(index).anyOf(valueArray).offset(N)
db.[table].where(index).above(value).and(filterFunction).offset(N)