can.observe.delegate.js | |
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/*!
* CanJS - 1.1.4 (2013-02-05)
* http://canjs.us/
* Copyright (c) 2013 Bitovi
* Licensed MIT
*/
(function (can, window, undefined) { | |
can/observe/delegate/delegate.js | |
| * - 'this' will be the deepest item changed * - 'this' will be any changes within *, but * will be the this returned tells if the parts part of a delegate matches the broken up props of the event gives the prop to use as 'this' - parts - the attribute name of the delegate split in parts ['foo',''] - props - the split props of the event that happened ['foo','bar','0'] - returns - the attribute to delegate too ('foo.bar'), or null if not a match | var matches = function (parts, props) { |
| check props parts are the same or | var len = parts.length,
i = 0, |
| keeps the matched props we will use | matchedProps = [],
prop; |
| if the event matches | for (i; i < len; i++) {
prop = props[i] |
| if no more props (but we should be matching them) return null | if (typeof prop !== 'string') {
return null;
} else |
| if we have a "**", match everything | if (parts[i] == "**") {
return props.join(".");
} else |
| a match, but we want to delegate to "*" | if (parts[i] == "*") { |
| only do this if there is nothing after ... | matchedProps.push(prop);
}
else if (prop === parts[i]) {
matchedProps.push(prop);
} else {
return null;
}
}
return matchedProps.join(".");
}, |
| gets a change event and tries to figure out which delegates to call | delegate = function (event, prop, how, newVal, oldVal) { |
| pre-split properties to save some regexp time | var props = prop.split("."),
delegates = (this._observe_delegates || []).slice(0),
delegate, attr, matchedAttr, hasMatch, valuesEqual;
event.attr = prop;
event.lastAttr = props[props.length - 1]; |
| for each delegate | for (var i = 0; delegate = delegates[i++];) { |
| if there is a batchNum, this means that this event is part of a series of events caused by a single attrs call. We don't want to issue the same event multiple times setting the batchNum happens later | if ((event.batchNum && delegate.batchNum === event.batchNum) || delegate.undelegated) {
continue;
} |
| reset match and values tests | hasMatch = undefined;
valuesEqual = true; |
| yeah, all this under here has to be redone v for each attr in a delegate | for (var a = 0; a < delegate.attrs.length; a++) {
attr = delegate.attrs[a]; |
| check if it is a match | if (matchedAttr = matches(attr.parts, props)) {
hasMatch = matchedAttr;
} |
| if it has a value, make sure it's the right value if it's set, we should probably check that it has a value no matter what | if (attr.value && valuesEqual) {
valuesEqual = attr.value === "" + this.attr(attr.attr)
} else if (valuesEqual && delegate.attrs.length > 1) { |
| if there are multiple attributes, each has to at least have some value | valuesEqual = this.attr(attr.attr) !== undefined
}
} |
| if there is a match and valuesEqual ... call back | if (hasMatch && valuesEqual) { |
| how to get to the changed property from the delegate | var from = prop.replace(hasMatch + ".", ""); |
| if this event is part of a batch, set it on the delegate to only send one event | if (event.batchNum) {
delegate.batchNum = event.batchNum
} |
| if we listen to change, fire those with the same attrs TODO: the attrs should probably be using from | if (delegate.event === 'change') {
arguments[1] = from;
event.curAttr = hasMatch;
delegate.callback.apply(this.attr(hasMatch), can.makeArray(arguments));
} else if (delegate.event === how) { |
| if it's a match, callback with the location of the match | delegate.callback.apply(this.attr(hasMatch), [event, newVal, oldVal, from]);
} else if (delegate.event === 'set' && how == 'add') { |
| if we are listening to set, we should also listen to add | delegate.callback.apply(this.attr(hasMatch), [event, newVal, oldVal, from]);
}
}
}
};
can.extend(can.Observe.prototype, {
delegate: function (selector, event, handler) {
selector = can.trim(selector);
var delegates = this._observe_delegates || (this._observe_delegates = []),
attrs = [],
selectorRegex = /([^\s=,]+)(?:=("[^",]*"|'[^',]*'|[^\s"',]*))?(,?)\s*/g,
matches; |
| parse each property in the selector | while (matches = selectorRegex.exec(selector)) { |
| we need to do a little doctoring to make up for the quotes. | if (matches[2] && $.inArray(matches[2].substr(0, 1), ['"', "'"]) >= 0) {
matches[2] = matches[2].substr(1, -1);
}
attrs.push({ |
| the attribute name | attr: matches[1], |
| the attribute name, pre-split for speed | parts: matches[1].split('.'), |
| the value associated with this property (if there was one given) | value: matches[2], |
| whether this selector combines with the one after it with AND or OR | or: matches[3] === ','
});
} |
| delegates has pre-processed info about the event | delegates.push({ |
| the attrs name for unbinding | selector: selector, |
| an object of attribute names and values {type: 'recipe',id: undefined} undefined means a value was not defined | attrs: attrs,
callback: handler,
event: event
});
if (delegates.length === 1) {
this.bind("change", delegate)
}
return this;
},
undelegate: function (selector, event, handler) {
selector = can.trim(selector);
var i = 0,
delegates = this._observe_delegates || [],
delegateOb;
if (selector) {
while (i < delegates.length) {
delegateOb = delegates[i];
if (delegateOb.callback === handler || (!handler && delegateOb.selector === selector)) {
delegateOb.undelegated = true;
delegates.splice(i, 1)
} else {
i++;
}
}
} else { |
| remove all delegates | delegates = [];
}
if (!delegates.length) { |
| can.removeData(this, "observedelegates"); | this.unbind("change", delegate)
}
return this;
}
}); |
| add helpers for testing .. | can.Observe.prototype.delegate.matches = matches;
})(can, this);
|