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The IDBKeyRange interface of the IndexedDB API represents a continuous interval over some data type that is used for keys. Records can be retrieved from IDBObjectStore and IDBIndex objects using keys or a range of keys. You can limit the range using lower and upper bounds. For example, you can iterate over all values of a key in the value range A–Z.

A key range can be a single value or a range with upper and lower bounds or endpoints. If the key range has both upper and lower bounds, then it is bounded; if it has no bounds, it is unbounded. A bounded key range can either be open (the endpoints are excluded) or closed (the endpoints are included). To retrieve all keys within a certain range, you can use the following code constructs:

Range Code
All keys ≤ x IDBKeyRange.upperBound(x)
All keys < x IDBKeyRange.upperBound(x, true)
All keys ≥ y IDBKeyRange.lowerBound(y)
All keys > y IDBKeyRange.lowerBound(y, true)
All keys ≥ x && ≤ y IDBKeyRange.bound(x, y)
All keys > x &&< y IDBKeyRange.bound(x, y, true, true)
All keys > x && ≤ y IDBKeyRange.bound(x, y, true, false)
All keys ≥ x &&< y IDBKeyRange.bound(x, y, false, true)
The key = z IDBKeyRange.only(z)

A key is in a key range if the following conditions are true:

  • The lower value of the key range is one of the following:
    • undefined
    • Less than key value
    • Equal to key value if lowerOpen is false.
  • The upper value of the key range is one of the following:
    • undefined
    • Greater than key value
    • Equal to key value if upperOpen is false.

Methods

IDBKeyRange.bound
Creates a new key range with upper and lower bounds.
IDBKeyRange.only
Creates a new key range containing a single value.
IDBKeyRange.lowerBound
Creates a new key range with only a lower bound.
IDBKeyRange.upperBound
Creates a new upper-bound key range.

Properties

IDBKeyRange.lower Read only
Lower bound of the key range.
IDBKeyRange.upper Read only
Upper bound of the key range.
IDBKeyRange.lowerOpen Read only
Returns false if the lower-bound value is included in the key range.
IDBKeyRange.upperOpen Read only
Returns false if the upper-bound value is included in the key range.

Examples

The following example illustrates how you'd use a key range. Here we declare a keyRangeValue as a range between values of "A" and "F". We open a transaction (using IDBTransaction) and an object store, and open a Cursor with IDBObjectStore.openCursor, declaring keyRangeValue as its optional key range value. This means that the cursor will only retrieve records with keys inside that range. This range includes the values "A" and "F", as we haven't declared that they should be open  bounds. If we used IDBKeyRange.bound("A", "F", true, true);, then the range would not include "A" and "F", only the values between them.

Note: For a more complete example allowing you to experiment with key range, have a look at our IDBKeyRange-example repo (view the example live too.)

function displayData() {
  var keyRangeValue = IDBKeyRange.bound("A", "F");

  var transaction = db.transaction(['fThings'], 'readonly');
  var objectStore = transaction.objectStore('fThings');

  objectStore.openCursor(keyRangeValue).onsuccess = function(event) {
    var cursor = event.target.result;
      if(cursor) {
        var listItem = document.createElement('li');
        listItem.innerHTML = '<strong>' + cursor.value.fThing + '</strong>, ' + cursor.value.fRating;
        list.appendChild(listItem);  
          
        cursor.continue();
      } else {
        console.log('Entries all displayed.');
      }
    };
  };

Specifications

Specification Status Comment
Indexed Database API
The definition of 'IDBKeyRange' in that specification.
Candidate Recommendation  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 23webkit
24
10 moz
16.0 (16.0)
10, partial 15 7.1
Feature Android Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support 4.4 22.0 (22.0) 1.0.1 10 22 Not supported

See also

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