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IDBKeyRange - Web APIs | MDN

 3 years ago
source link: https://developer.mozilla.org/en-US/docs/Web/API/IDBKeyRange
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IDBKeyRange

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.lowerBound(x) All keys > x IDBKeyRange.lowerBound(x, true) All keys ≤ y IDBKeyRange.upperBound(y) All keys < y IDBKeyRange.upperBound(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.

Note: This feature is available in Web Workers

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.

Methods

Static 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.

Instance methods

IDBKeyRange.includes() Returns a boolean indicating whether a specified key is inside 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

SpecificationIndexed Database API 3.0 (Indexed DB 3.0)
# keyrange

Browser compatibility

Report problems with this compatibility data on GitHubdesktopmobileChromeEdgeFirefoxInternet ExplorerOperaSafariWebView AndroidChrome AndroidFirefox for AndroidOpera AndroidSafari on iOSSamsung Internet
IDBKeyRange
Full support24Full support12Full support16Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYesboundFull support23Full support12Full support10Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYesincludesFull support52Full support18Full support47No supportNoFull support39Full support10.1Full support52Full support52Full supportYesFull support41Full support10.3Full support6.0lowerFull support23Full support12Full support10Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYeslowerBoundFull support23Full support12Full support10Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYeslowerOpenFull support23Full support12Full support10Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYesonlyFull support23Full support12Full support10Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYesupperFull support23Full support12Full support10Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYesupperBoundFull support23Full support12Full support10Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYesupperOpenFull support23Full support12Full support10Partial support10Full support15Full support7Full supportYesFull supportYesFull support22Full support14Full support8Full supportYes
Available in workers
Full support23Full support12Full support37Full support10Full support15Full support10Full support37Full support25Full support37Full support14Full support10Full support1.5

Legend

Full supportFull support
Partial supportPartial support
No supportNo support
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