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    IDBKeyRange

    This article is in need of a technical review.

    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

    Document Tags and Contributors

    Last updated by: chrisdavidmills,