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    Summary

    Binds an object property to a function that will be called when that property is looked up.

    Syntax

    {get prop() { . . . } }

    Parameters

    prop
    the name of the property to bind to the given function

    Description

    Sometimes it is desirable to allow access to a property that returns a dynamically computed value, or you may want reflect the status of an internal variable without requiring the use of explicit method calls. In JavaScript, this can be accomplished with the use of a getter. It is not possible to simultaneously have a getter bound to a property and have that property actually hold a value, although it is possible to use a getter and a setter in conjunction to create a type of pseudo-property.

    JavaScript 1.8.5 note

    Starting in JavaScript 1.8.5, the get operator:

    A getter can be removed using the delete operator.

    Examples

    Defining a getter with the get operator

    This will create a pseudo-property latest for object obj, which will return the last array item in log. Note: to append a getter to an existing object, use Object.defineProperty().

    var log = ['test'];
    var obj = {
      get latest () {
        if (log.length == 0) return undefined;
        return log[log.length - 1]
      }
    }
    console.log (obj.latest); // Will return "test".
    

    Note that attempting to assign a value to latest will not change it.

    Deleting a getter using the delete operator

    delete obj.latest;
    

    Browser compatibility

    Based on Robert Nyman's page

    No support (notably in IE6-8) means that the script will trigger a syntax error.

    Feature Firefox (Gecko) Chrome Internet Explorer Opera Safari
    Basic support 2.0 (1.8.1) 1 9 9.5 3
    Feature Firefox Mobile (Gecko) Android IE Mobile Opera Mobile Safari Mobile
    Basic support ? ? ? ? ?

    See also

     

    Document Tags and Contributors

    Contributors to this page: Sheppy
    Last updated by: Sheppy,