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// REPEAT binding for Knockout http://knockoutjs.com/
// (c) Michael Best
// License: MIT (http://www.opensource.org/licenses/mit-license.php)
// Version 2.1.0
(function(factory) {
if (typeof define === 'function' && define.amd) {
// [1] AMD anonymous module
define(['knockout'], factory);
} else if (typeof exports === 'object') {
// [2] commonJS
factory(require('knockout'));
} else {
// [3] No module loader (plain <script> tag) - put directly in global namespace
factory(window.ko);
}
})(function(ko) {
if (!ko.virtualElements)
throw Error('Repeat requires at least Knockout 2.1');
var ko_bindingFlags = ko.bindingFlags || {};
var ko_unwrap = ko.utils.unwrapObservable;
var koProtoName = '__ko_proto__';
if (ko.version >= "3.0.0") {
// In Knockout 3.0.0, use the node preprocessor to replace a node with a repeat binding with a virtual element
var provider = ko.bindingProvider.instance, previousPreprocessFn = provider.preprocessNode;
provider.preprocessNode = function(node) {
var newNodes, nodeBinding;
if (!previousPreprocessFn || !(newNodes = previousPreprocessFn.call(this, node))) {
if (node.nodeType === 1 && (nodeBinding = node.getAttribute('data-bind'))) {
if (/^\s*repeat\s*:/.test(nodeBinding)) {
var leadingComment = node.ownerDocument.createComment('ko ' + nodeBinding),
trailingComment = node.ownerDocument.createComment('/ko');
node.parentNode.insertBefore(leadingComment, node);
node.parentNode.insertBefore(trailingComment, node.nextSibling);
node.removeAttribute('data-bind');
newNodes = [leadingComment, node, trailingComment];
}
}
}
return newNodes;
};
}
ko.virtualElements.allowedBindings.repeat = true;
ko.bindingHandlers.repeat = {
flags: ko_bindingFlags.contentBind | ko_bindingFlags.canUseVirtual,
init: function(element, valueAccessor, allBindingsAccessor, xxx, bindingContext) {
// Read and set fixed options--these options cannot be changed
var repeatParam = ko_unwrap(valueAccessor());
if (repeatParam && typeof repeatParam == 'object' && !('length' in repeatParam)) {
var repeatIndex = repeatParam.index,
repeatData = repeatParam.item,
repeatStep = repeatParam.step,
repeatReversed = repeatParam.reverse,
repeatBind = repeatParam.bind,
repeatInit = repeatParam.init,
repeatUpdate = repeatParam.update;
}
// Set default values for options that need it
repeatIndex = repeatIndex || '$index';
repeatData = repeatData || ko.bindingHandlers.repeat.itemName || '$item';
repeatStep = repeatStep || 1;
repeatReversed = repeatReversed || false;
var parent = element.parentNode, placeholder;
if (element.nodeType == 8) { // virtual element
// Extract the "children" and find the single element node
var childNodes = ko.utils.arrayFilter(ko.virtualElements.childNodes(element), function(node) { return node.nodeType == 1;});
if (childNodes.length !== 1) {
throw Error("Repeat binding requires a single element to repeat");
}
ko.virtualElements.emptyNode(element);
// The placeholder is the closing comment normally, or the opening comment if reversed
placeholder = repeatReversed ? element : element.nextSibling;
// The element to repeat is the contained element
element = childNodes[0];
} else { // regular element
// First clean the element node and remove node's binding
var origBindString = element.getAttribute('data-bind');
ko.cleanNode(element);
element.removeAttribute('data-bind');
// Original element is no longer needed: delete it and create a placeholder comment
placeholder = element.ownerDocument.createComment('ko_repeatplaceholder ' + origBindString);
parent.replaceChild(placeholder, element);
}
// extract and remove a data-repeat-bind attribute, if present
if (!repeatBind) {
repeatBind = element.getAttribute('data-repeat-bind');
if (repeatBind) {
element.removeAttribute('data-repeat-bind');
}
}
// Make a copy of the element node to be copied for each repetition
var cleanNode = element.cloneNode(true);
if (typeof repeatBind == "string") {
cleanNode.setAttribute('data-bind', repeatBind);
repeatBind = null;
}
// Set up persistent data
var lastRepeatCount = 0,
notificationObservable = ko.observable(),
repeatArray, arrayObservable;
if (repeatInit) {
repeatInit(parent);
}
var subscribable = ko.computed(function() {
function makeArrayItemAccessor(index) {
var f = function(newValue) {
var item = repeatArray[index];
// Reading the value of the item
if (!arguments.length) {
notificationObservable(); // for dependency tracking
return ko_unwrap(item);
}
// Writing a value to the item
if (ko.isObservable(item)) {
item(newValue);
} else if (arrayObservable && arrayObservable.splice) {
arrayObservable.splice(index, 1, newValue);
} else {
repeatArray[index] = newValue;
}
return this;
};
// Pretend that our accessor function is an observable
f[koProtoName] = ko.observable;
return f;
}
function makeBinding(item, index, context) {
return repeatArray
? function() { return repeatBind.call(bindingContext.$data, item, index, context); }
: function() { return repeatBind.call(bindingContext.$data, index, context); }
}
// Read and set up variable options--these options can change and will update the binding
var paramObservable = valueAccessor(), repeatParam = ko_unwrap(paramObservable), repeatCount = 0;
if (repeatParam && typeof repeatParam == 'object') {
if ('length' in repeatParam) {
repeatArray = repeatParam;
repeatCount = repeatArray.length;
} else {
if ('foreach' in repeatParam) {
repeatArray = ko_unwrap(paramObservable = repeatParam.foreach);
if (repeatArray && typeof repeatArray == 'object' && 'length' in repeatArray) {
repeatCount = repeatArray.length || 0;
} else {
repeatCount = repeatArray || 0;
repeatArray = null;
}
}
// If a count value is provided (>0), always output that number of items
if ('count' in repeatParam)
repeatCount = ko_unwrap(repeatParam.count) || repeatCount;
// If a limit is provided, don't output more than the limit
if ('limit' in repeatParam)
repeatCount = Math.min(repeatCount, ko_unwrap(repeatParam.limit)) || repeatCount;
}
arrayObservable = repeatArray && ko.isObservable(paramObservable) ? paramObservable : null;
} else {
repeatCount = repeatParam || 0;
}
// Remove nodes from end if array is shorter
for (; lastRepeatCount > repeatCount; lastRepeatCount-=repeatStep) {
ko.removeNode(repeatReversed ? placeholder.nextSibling : placeholder.previousSibling);
}
// Notify existing nodes of change
notificationObservable.notifySubscribers();
// Add nodes to end if array is longer (also initially populates nodes)
for (; lastRepeatCount < repeatCount; lastRepeatCount+=repeatStep) {
// Clone node and add to document
var newNode = cleanNode.cloneNode(true);
parent.insertBefore(newNode, repeatReversed ? placeholder.nextSibling : placeholder);
newNode.setAttribute('data-repeat-index', lastRepeatCount);
// Apply bindings to inserted node
if (repeatArray && repeatData == '$data') {
var newContext = bindingContext.createChildContext(makeArrayItemAccessor(lastRepeatCount));
} else {
var newContext = bindingContext.extend();
if (repeatArray)
newContext[repeatData] = makeArrayItemAccessor(lastRepeatCount);
}
newContext[repeatIndex] = lastRepeatCount;
if (repeatBind) {
var result = ko.applyBindingsToNode(newNode, makeBinding(newContext[repeatData], lastRepeatCount, newContext), newContext, true),
shouldBindDescendants = result && result.shouldBindDescendants;
}
if (!repeatBind || (result && shouldBindDescendants !== false)) {
ko.applyBindings(newContext, newNode);
}
}
if (repeatUpdate) {
repeatUpdate(parent);
}
}, null, {disposeWhenNodeIsRemoved: placeholder});
return { controlsDescendantBindings: true, subscribable: subscribable };
}
};
});