/**
Adds a synthetic `valuechange` event that fires when the `value` property of an
`<input>` or `<textarea>` node changes as a result of a keystroke, mouse
operation, or input method editor (IME) input event.
Usage:
YUI().use('event-valuechange', function (Y) {
Y.one('#my-input').on('valuechange', function (e) {
Y.log('previous value: ' + e.prevVal);
Y.log('new value: ' + e.newVal);
});
});
@module event-valuechange
**/
/**
Provides the implementation for the synthetic `valuechange` event. This class
isn't meant to be used directly, but is public to make monkeypatching possible.
Usage:
YUI().use('event-valuechange', function (Y) {
Y.one('#my-input').on('valuechange', function (e) {
Y.log('previous value: ' + e.prevVal);
Y.log('new value: ' + e.newVal);
});
});
@class ValueChange
@static
*/
var DATA_KEY = '_valuechange',
VALUE = 'value',
config, // defined at the end of this file
// Just a simple namespace to make methods overridable.
VC = {
// -- Static Constants -----------------------------------------------------
/**
Interval (in milliseconds) at which to poll for changes to the value of an
element with one or more `valuechange` subscribers when the user is likely
to be interacting with it.
@property POLL_INTERVAL
@type Number
@default 50
@static
**/
POLL_INTERVAL: 50,
/**
Timeout (in milliseconds) after which to stop polling when there hasn't been
any new activity (keypresses, mouse clicks, etc.) on an element.
@property TIMEOUT
@type Number
@default 10000
@static
**/
TIMEOUT: 10000,
// -- Protected Static Methods ---------------------------------------------
/**
Called at an interval to poll for changes to the value of the specified
node.
@method _poll
@param {Node} node Node to poll.
@param {Object} options Options object.
@param {EventFacade} [options.e] Event facade of the event that
initiated the polling.
@protected
@static
**/
_poll: function (node, options) {
var domNode = node._node, // performance cheat; getValue() is a big hit when polling
event = options.e,
newVal = domNode && domNode.value,
vcData = node._data && node._data[DATA_KEY], // another perf cheat
facade, prevVal;
if (!domNode || !vcData) {
Y.log('_poll: node #' + node.get('id') + ' disappeared; stopping polling and removing all notifiers.', 'warn', 'event-valuechange');
VC._stopPolling(node);
return;
}
prevVal = vcData.prevVal;
if (newVal !== prevVal) {
vcData.prevVal = newVal;
facade = {
_event : event,
currentTarget: (event && event.currentTarget) || node,
newVal : newVal,
prevVal : prevVal,
target : (event && event.target) || node
};
Y.Object.each(vcData.notifiers, function (notifier) {
notifier.fire(facade);
});
VC._refreshTimeout(node);
}
},
/**
Restarts the inactivity timeout for the specified node.
@method _refreshTimeout
@param {Node} node Node to refresh.
@param {SyntheticEvent.Notifier} notifier
@protected
@static
**/
_refreshTimeout: function (node, notifier) {
// The node may have been destroyed, so check that it still exists
// before trying to get its data. Otherwise an error will occur.
if (!node._node) {
Y.log('_stopPolling: node disappeared', 'warn', 'event-valuechange');
return;
}
var vcData = node.getData(DATA_KEY);
VC._stopTimeout(node); // avoid dupes
// If we don't see any changes within the timeout period (10 seconds by
// default), stop polling.
vcData.timeout = setTimeout(function () {
Y.log('timeout: #' + node.get('id'), 'info', 'event-valuechange');
VC._stopPolling(node, notifier);
}, VC.TIMEOUT);
Y.log('_refreshTimeout: #' + node.get('id'), 'info', 'event-valuechange');
},
/**
Begins polling for changes to the `value` property of the specified node. If
polling is already underway for the specified node, it will not be restarted
unless the `force` option is `true`
@method _startPolling
@param {Node} node Node to watch.
@param {SyntheticEvent.Notifier} notifier
@param {Object} options Options object.
@param {EventFacade} [options.e] Event facade of the event that
initiated the polling.
@param {Boolean} [options.force=false] If `true`, polling will be
restarted even if we're already polling this node.
@protected
@static
**/
_startPolling: function (node, notifier, options) {
if (!node.test('input,textarea')) {
Y.log('_startPolling: aborting poll on #' + node.get('id') + ' -- not an input or textarea', 'warn', 'event-valuechange');
return;
}
var vcData = node.getData(DATA_KEY);
if (!vcData) {
vcData = {prevVal: node.get(VALUE)};
node.setData(DATA_KEY, vcData);
}
vcData.notifiers || (vcData.notifiers = {});
// Don't bother continuing if we're already polling this node, unless
// `options.force` is true.
if (vcData.interval) {
if (options.force) {
VC._stopPolling(node, notifier); // restart polling, but avoid dupe polls
} else {
vcData.notifiers[Y.stamp(notifier)] = notifier;
return;
}
}
// Poll for changes to the node's value. We can't rely on keyboard
// events for this, since the value may change due to a mouse-initiated
// paste event, an IME input event, or for some other reason that
// doesn't trigger a key event.
vcData.notifiers[Y.stamp(notifier)] = notifier;
vcData.interval = setInterval(function () {
VC._poll(node, vcData, options);
}, VC.POLL_INTERVAL);
Y.log('_startPolling: #' + node.get('id'), 'info', 'event-valuechange');
VC._refreshTimeout(node, notifier);
},
/**
Stops polling for changes to the specified node's `value` attribute.
@method _stopPolling
@param {Node} node Node to stop polling on.
@param {SyntheticEvent.Notifier} [notifier] Notifier to remove from the
node. If not specified, all notifiers will be removed.
@protected
@static
**/
_stopPolling: function (node, notifier) {
// The node may have been destroyed, so check that it still exists
// before trying to get its data. Otherwise an error will occur.
if (!node._node) {
Y.log('_stopPolling: node disappeared', 'info', 'event-valuechange');
return;
}
var vcData = node.getData(DATA_KEY) || {};
clearInterval(vcData.interval);
delete vcData.interval;
VC._stopTimeout(node);
if (notifier) {
vcData.notifiers && delete vcData.notifiers[Y.stamp(notifier)];
} else {
vcData.notifiers = {};
}
Y.log('_stopPolling: #' + node.get('id'), 'info', 'event-valuechange');
},
/**
Clears the inactivity timeout for the specified node, if any.
@method _stopTimeout
@param {Node} node
@protected
@static
**/
_stopTimeout: function (node) {
var vcData = node.getData(DATA_KEY) || {};
clearTimeout(vcData.timeout);
delete vcData.timeout;
},
// -- Protected Static Event Handlers --------------------------------------
/**
Stops polling when a node's blur event fires.
@method _onBlur
@param {EventFacade} e
@param {SyntheticEvent.Notifier} notifier
@protected
@static
**/
_onBlur: function (e, notifier) {
VC._stopPolling(e.currentTarget, notifier);
},
/**
Resets a node's history and starts polling when a focus event occurs.
@method _onFocus
@param {EventFacade} e
@param {SyntheticEvent.Notifier} notifier
@protected
@static
**/
_onFocus: function (e, notifier) {
var node = e.currentTarget,
vcData = node.getData(DATA_KEY);
if (!vcData) {
vcData = {};
node.setData(DATA_KEY, vcData);
}
vcData.prevVal = node.get(VALUE);
VC._startPolling(node, notifier, {e: e});
},
/**
Starts polling when a node receives a keyDown event.
@method _onKeyDown
@param {EventFacade} e
@param {SyntheticEvent.Notifier} notifier
@protected
@static
**/
_onKeyDown: function (e, notifier) {
VC._startPolling(e.currentTarget, notifier, {e: e});
},
/**
Starts polling when an IME-related keyUp event occurs on a node.
@method _onKeyUp
@param {EventFacade} e
@param {SyntheticEvent.Notifier} notifier
@protected
@static
**/
_onKeyUp: function (e, notifier) {
// These charCodes indicate that an IME has started. We'll restart
// polling and give the IME up to 10 seconds (by default) to finish.
if (e.charCode === 229 || e.charCode === 197) {
VC._startPolling(e.currentTarget, notifier, {
e : e,
force: true
});
}
},
/**
Starts polling when a node receives a mouseDown event.
@method _onMouseDown
@param {EventFacade} e
@param {SyntheticEvent.Notifier} notifier
@protected
@static
**/
_onMouseDown: function (e, notifier) {
VC._startPolling(e.currentTarget, notifier, {e: e});
},
/**
Called when the `valuechange` event receives a new subscriber.
@method _onSubscribe
@param {Node} node
@param {Subscription} sub
@param {SyntheticEvent.Notifier} notifier
@param {Function|String} [filter] Filter function or selector string. Only
provided for delegate subscriptions.
@protected
@static
**/
_onSubscribe: function (node, sub, notifier, filter) {
var _valuechange, callbacks, nodes;
callbacks = {
blur : VC._onBlur,
focus : VC._onFocus,
keydown : VC._onKeyDown,
keyup : VC._onKeyUp,
mousedown: VC._onMouseDown
};
// Store a utility object on the notifier to hold stuff that needs to be
// passed around to trigger event handlers, polling handlers, etc.
_valuechange = notifier._valuechange = {};
if (filter) {
// If a filter is provided, then this is a delegated subscription.
_valuechange.delegated = true;
// Add a function to the notifier that we can use to find all
// nodes that pass the delegate filter.
_valuechange.getNodes = function () {
return node.all('input,textarea').filter(filter);
};
// Store the initial values for each descendant of the container
// node that passes the delegate filter.
_valuechange.getNodes().each(function (child) {
if (!child.getData(DATA_KEY)) {
child.setData(DATA_KEY, {prevVal: child.get(VALUE)});
}
});
notifier._handles = Y.delegate(callbacks, node, filter, null,
notifier);
} else {
// This is a normal (non-delegated) event subscription.
if (!node.test('input,textarea')) {
return;
}
if (!node.getData(DATA_KEY)) {
node.setData(DATA_KEY, {prevVal: node.get(VALUE)});
}
notifier._handles = node.on(callbacks, null, null, notifier);
}
},
/**
Called when the `valuechange` event loses a subscriber.
@method _onUnsubscribe
@param {Node} node
@param {Subscription} subscription
@param {SyntheticEvent.Notifier} notifier
@protected
@static
**/
_onUnsubscribe: function (node, subscription, notifier) {
var _valuechange = notifier._valuechange;
notifier._handles && notifier._handles.detach();
if (_valuechange.delegated) {
_valuechange.getNodes().each(function (child) {
VC._stopPolling(child, notifier);
});
} else {
VC._stopPolling(node, notifier);
}
}
};
/**
Synthetic event that fires when the `value` property of an `<input>` or
`<textarea>` node changes as a result of a user-initiated keystroke, mouse
operation, or input method editor (IME) input event.
Unlike the `onchange` event, this event fires when the value actually changes
and not when the element loses focus. This event also reports IME and
multi-stroke input more reliably than `oninput` or the various key events across
browsers.
For performance reasons, only focused nodes are monitored for changes, so
programmatic value changes on nodes that don't have focus won't be detected.
@example
YUI().use('event-valuechange', function (Y) {
Y.one('#my-input').on('valuechange', function (e) {
Y.log('previous value: ' + e.prevVal);
Y.log('new value: ' + e.newVal);
});
});
@event valuechange
@param {String} prevVal Previous value prior to the latest change.
@param {String} newVal New value after the latest change.
@for YUI
**/
config = {
detach: VC._onUnsubscribe,
on : VC._onSubscribe,
delegate : VC._onSubscribe,
detachDelegate: VC._onUnsubscribe,
publishConfig: {
emitFacade: true
}
};
Y.Event.define('valuechange', config);
Y.Event.define('valueChange', config); // deprecated, but supported for backcompat
Y.ValueChange = VC;
