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virtual-repeater.js
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virtual-repeater.js
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/**
* @ngdoc module
* @name material.components.virtualRepeat
*/
angular.module('virtualRepeat', [])
.config(setupCSS)
.directive('mdVirtualRepeatContainer', VirtualRepeatContainerDirective)
.directive('mdVirtualRepeat', ['$parse', VirtualRepeatDirective])
.directive('mdForceHeight', ForceHeightDirective)
.factory('$mdUtil', UtilFactory)
.factory('$mdConstant', MdConstantFactory);
function UtilFactory($rootScope, $timeout) {
var $mdUtil = {
// Returns a function, that, as long as it continues to be invoked, will not
// be triggered. The function will be called after it stops being called for
// N milliseconds.
// @param wait Integer value of msecs to delay (since last debounce reset); default value 10 msecs
// @param invokeApply should the $timeout trigger $digest() dirty checking
debounce: function(func, wait, scope, invokeApply) {
var timer;
return function debounced() {
var context = scope,
args = Array.prototype.slice.call(arguments);
$timeout.cancel(timer);
timer = $timeout(function() {
timer = undefined;
func.apply(context, args);
}, wait || 10, invokeApply);
};
},
/**
* Parses an attribute value, mostly a string.
* By default checks for negated values and returns `false´ if present.
* Negated values are: (native falsy) and negative strings like:
* `false` or `0`.
* @param value Attribute value which should be parsed.
* @param negatedCheck When set to false, won't check for negated values.
* @returns {boolean}
*/
parseAttributeBoolean: function(value, negatedCheck) {
return value === '' || !!value && (negatedCheck === false || value !== 'false' && value !== '0');
},
/**
* Alternative to $timeout calls with 0 delay.
* nextTick() coalesces all calls within a single frame
* to minimize $digest thrashing
*
* @param callback
* @param digest
* @returns {*}
*/
nextTick: function(callback, digest, scope) {
//-- grab function reference for storing state details
var nextTick = $mdUtil.nextTick;
var timeout = nextTick.timeout;
var queue = nextTick.queue || [];
//-- add callback to the queue
queue.push({scope: scope, callback: callback});
//-- set default value for digest
if (digest == null) digest = true;
//-- store updated digest/queue values
nextTick.digest = nextTick.digest || digest;
nextTick.queue = queue;
//-- either return existing timeout or create a new one
return timeout || (nextTick.timeout = $timeout(processQueue, 0, false));
/**
* Grab a copy of the current queue
* Clear the queue for future use
* Process the existing queue
* Trigger digest if necessary
*/
function processQueue() {
var queue = nextTick.queue;
var digest = nextTick.digest;
nextTick.queue = [];
nextTick.timeout = null;
nextTick.digest = false;
queue.forEach(function(queueItem) {
var skip = queueItem.scope && queueItem.scope.$$destroyed;
if (!skip) {
queueItem.callback();
}
});
if (digest) $rootScope.$digest();
}
},
};
return $mdUtil;
}
UtilFactory.$inject = ['$rootScope', '$timeout'];
function MdConstantFactory() {
var self = {
ELEMENT_MAX_PIXELS: 1533917,
};
return self;
}
function setupCSS() {
var styleEl = document.createElement('style');
var virtualRepeatContainer = [
'box-sizing: border-box;',
'display: block;',
'margin: 0;',
'overflow: hidden;',
'padding: 0;',
'position: relative;'
];
var virtualRepeatContainer_virtualRepeatScroller = [
'bottom: 0;',
'box-sizing: border-box;',
'left: 0;',
'margin: 0;',
'overflow-x: hidden;',
'padding: 0;',
'position: absolute;',
'right: 0;',
'top: 0;',
'-webkit-overflow-scrolling: touch;'
];
var virtualRepeatContainer_virtualRepeatSizer = [
'box-sizing: border-box;',
'height: 1px;',
'display: block;',
'margin: 0;',
'padding: 0;',
'width: 1px;'
];
var virtualRepeatContainer_virtualRepeatOffsetter = [
'box-sizing: border-box;',
'left: 0;',
'margin: 0;',
'padding: 0;',
'position: absolute;',
'right: 0;',
'top: 0;'
];
var virtualRepeatContainerOrientHorizontal_virtualRepeatScroller = [
'overflow-x: auto;',
'overflow-y: hidden;'
];
var virtualRepeatContainerOrientHorizontal_virtualRepeatOffsetter = [
'bottom: 16px;',
'right: auto;',
'white-space: nowrap;'
];
document.head.appendChild(styleEl);
var styleSheet = styleEl.sheet;
styleSheet.insertRule('.md-virtual-repeat-container {' + virtualRepeatContainer.join('') + '}', 0);
styleSheet.insertRule('.md-virtual-repeat-container .md-virtual-repeat-scroller {' + virtualRepeatContainer_virtualRepeatScroller.join('') + '}', 0);
styleSheet.insertRule('.md-virtual-repeat-container .md-virtual-repeat-sizer {' + virtualRepeatContainer_virtualRepeatSizer.join('') + '}', 0);
styleSheet.insertRule('.md-virtual-repeat-container .md-virtual-repeat-offsetter {' + virtualRepeatContainer_virtualRepeatOffsetter.join('') + '}', 0);
styleSheet.insertRule('.md-virtual-repeat-container.md-orient-horizontal .md-virtual-repeat-scroller {' + virtualRepeatContainerOrientHorizontal_virtualRepeatScroller.join('') + '}', 0);
styleSheet.insertRule('.md-virtual-repeat-container.md-orient-horizontal .md-virtual-repeat-offsetter {' + virtualRepeatContainerOrientHorizontal_virtualRepeatOffsetter.join('') + '}', 0);
}
/**
* @ngdoc directive
* @name mdVirtualRepeatContainer
* @module material.components.virtualRepeat
* @restrict E
* @description
* `md-virtual-repeat-container` provides the scroll container for md-virtual-repeat.
*
* VirtualRepeat is a limited substitute for ng-repeat that renders only
* enough DOM nodes to fill the container and recycling them as the user scrolls.
*
* Once an element is not visible anymore, the VirtualRepeat recycles it and will reuse it for
* another visible item by replacing the previous dataset with the new one.
*
* ### Common Issues
*
* - When having one-time bindings inside of the view template, the VirtualRepeat will not properly
* update the bindings for new items, since the view will be recycled.
*
* - Directives inside of a VirtualRepeat will be only compiled (linked) once, because those
* are will be recycled items and used for other items.
* The VirtualRepeat just updates the scope bindings.
*
*
* ### Notes
*
* > The VirtualRepeat is a similar implementation to the Android
* [RecyclerView](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html)
*
* <!-- This comment forces a break between blockquotes //-->
*
* > Please also review the <a ng-href="api/directive/mdVirtualRepeat">VirtualRepeat</a>
* documentation for more information.
*
*
* @usage
* <hljs lang="html">
*
* <md-virtual-repeat-container md-top-index="topIndex">
* <div md-virtual-repeat="i in items" md-item-size="20">Hello {{i}}!</div>
* </md-virtual-repeat-container>
* </hljs>
*
* @param {number=} md-top-index Binds the index of the item that is at the top of the scroll
* container to $scope. It can both read and set the scroll position.
* @param {boolean=} md-orient-horizontal Whether the container should scroll horizontally
* (defaults to orientation and scrolling vertically).
* @param {boolean=} md-auto-shrink When present, the container will shrink to fit
* the number of items when that number is less than its original size.
* @param {number=} md-auto-shrink-min Minimum number of items that md-auto-shrink
* will shrink to (default: 0).
*/
function VirtualRepeatContainerDirective() {
return {
controller: VirtualRepeatContainerController,
template: virtualRepeatContainerTemplate,
compile: function virtualRepeatContainerCompile($element, $attrs) {
$element
.addClass('md-virtual-repeat-container')
.addClass($attrs.hasOwnProperty('mdOrientHorizontal')
? 'md-orient-horizontal'
: 'md-orient-vertical');
}
};
}
function virtualRepeatContainerTemplate($element) {
return '<div class="md-virtual-repeat-scroller" role="presentation">' +
'<div class="md-virtual-repeat-sizer" role="presentation"></div>' +
'<div class="md-virtual-repeat-offsetter" role="presentation">' +
$element[0].innerHTML +
'</div></div>';
}
/**
* Number of additional elements to render above and below the visible area inside
* of the virtual repeat container. A higher number results in less flicker when scrolling
* very quickly in Safari, but comes with a higher rendering and dirty-checking cost.
* @const {number}
*/
var NUM_EXTRA = 3;
/** @ngInject */
function VirtualRepeatContainerController($$rAF, $mdUtil, $mdConstant, $parse, $rootScope, $window, $scope,
$element, $attrs) {
this.$rootScope = $rootScope;
this.$scope = $scope;
this.$element = $element;
this.$attrs = $attrs;
/** @type {number} The width or height of the container */
this.size = 0;
/** @type {number} The scroll width or height of the scroller */
this.scrollSize = 0;
/** @type {number} The scrollLeft or scrollTop of the scroller */
this.scrollOffset = 0;
/** @type {boolean} Whether the scroller is oriented horizontally */
this.horizontal = this.$attrs.hasOwnProperty('mdOrientHorizontal');
/** @type {!VirtualRepeatController} The repeater inside of this container */
this.repeater = null;
/** @type {boolean} Whether auto-shrink is enabled */
this.autoShrink = this.$attrs.hasOwnProperty('mdAutoShrink');
/** @type {number} Minimum number of items to auto-shrink to */
this.autoShrinkMin = parseInt(this.$attrs.mdAutoShrinkMin, 10) || 0;
/** @type {?number} Original container size when shrank */
this.originalSize = null;
/** @type {number} Amount to offset the total scroll size by. */
this.offsetSize = parseInt(this.$attrs.mdOffsetSize, 10) || 0;
/** @type {?string} height or width element style on the container prior to auto-shrinking. */
this.oldElementSize = null;
/** @type {!number} Maximum amount of pixels allowed for a single DOM element */
this.maxElementPixels = $mdConstant.ELEMENT_MAX_PIXELS;
if (this.$attrs.mdTopIndex) {
/** @type {function(angular.Scope): number} Binds to topIndex on AngularJS scope */
this.bindTopIndex = $parse(this.$attrs.mdTopIndex);
/** @type {number} The index of the item that is at the top of the scroll container */
this.topIndex = this.bindTopIndex(this.$scope);
if (!angular.isDefined(this.topIndex)) {
this.topIndex = 0;
this.bindTopIndex.assign(this.$scope, 0);
}
this.$scope.$watch(this.bindTopIndex, angular.bind(this, function(newIndex) {
if (newIndex !== this.topIndex) {
this.scrollToIndex(newIndex);
}
}));
} else {
this.topIndex = 0;
}
this.scroller = $element[0].querySelector('.md-virtual-repeat-scroller');
this.sizer = this.scroller.querySelector('.md-virtual-repeat-sizer');
this.offsetter = this.scroller.querySelector('.md-virtual-repeat-offsetter');
// After the dom stablizes, measure the initial size of the container and
// make a best effort at re-measuring as it changes.
var boundUpdateSize = angular.bind(this, this.updateSize);
$$rAF(angular.bind(this, function() {
boundUpdateSize();
var debouncedUpdateSize = $mdUtil.debounce(boundUpdateSize, 10, null, false);
var jWindow = angular.element($window);
// Make one more attempt to get the size if it is 0.
// This is not by any means a perfect approach, but there's really no
// silver bullet here.
if (!this.size) {
debouncedUpdateSize();
}
jWindow.on('resize', debouncedUpdateSize);
$scope.$on('$destroy', function() {
jWindow.off('resize', debouncedUpdateSize);
});
$scope.$emit('$md-resize-enable');
$scope.$on('$md-resize', boundUpdateSize);
}));
}
/** Called by the md-virtual-repeat inside of the container at startup. */
VirtualRepeatContainerController.prototype.register = function(repeaterCtrl) {
this.repeater = repeaterCtrl;
angular.element(this.scroller)
.on('scroll wheel touchmove touchend', angular.bind(this, this.handleScroll_));
};
/** @return {boolean} Whether the container is configured for horizontal scrolling. */
VirtualRepeatContainerController.prototype.isHorizontal = function() {
return this.horizontal;
};
/** @return {number} The size (width or height) of the container. */
VirtualRepeatContainerController.prototype.getSize = function() {
return this.size;
};
/**
* Resizes the container.
* @private
* @param {number} size The new size to set.
*/
VirtualRepeatContainerController.prototype.setSize_ = function(size) {
var dimension = this.getDimensionName_();
this.size = size;
this.$element[0].style[dimension] = size + 'px';
};
VirtualRepeatContainerController.prototype.unsetSize_ = function() {
this.$element[0].style[this.getDimensionName_()] = this.oldElementSize;
this.oldElementSize = null;
};
/** Instructs the container to re-measure its size. */
VirtualRepeatContainerController.prototype.updateSize = function() {
// If the original size is already determined, we can skip the update.
if (this.originalSize) return;
this.size = this.isHorizontal()
? this.$element[0].clientWidth
: this.$element[0].clientHeight;
// Recheck the scroll position after updating the size. This resolves
// problems that can result if the scroll position was measured while the
// element was display: none or detached from the document.
this.handleScroll_();
this.repeater && this.repeater.containerUpdated();
};
/** @return {number} The container's scrollHeight or scrollWidth. */
VirtualRepeatContainerController.prototype.getScrollSize = function() {
return this.scrollSize;
};
VirtualRepeatContainerController.prototype.getDimensionName_ = function() {
return this.isHorizontal() ? 'width' : 'height';
};
/**
* Sets the scroller element to the specified size.
* @private
* @param {number} size The new size.
*/
VirtualRepeatContainerController.prototype.sizeScroller_ = function(size) {
var dimension = this.getDimensionName_();
var crossDimension = this.isHorizontal() ? 'height' : 'width';
// Clear any existing dimensions.
this.sizer.innerHTML = '';
// If the size falls within the browser's maximum explicit size for a single element, we can
// set the size and be done. Otherwise, we have to create children that add up the the desired
// size.
if (size < this.maxElementPixels) {
this.sizer.style[dimension] = size + 'px';
} else {
this.sizer.style[dimension] = 'auto';
this.sizer.style[crossDimension] = 'auto';
// Divide the total size we have to render into N max-size pieces.
var numChildren = Math.floor(size / this.maxElementPixels);
// Element template to clone for each max-size piece.
var sizerChild = document.createElement('div');
sizerChild.style[dimension] = this.maxElementPixels + 'px';
sizerChild.style[crossDimension] = '1px';
for (var i = 0; i < numChildren; i++) {
this.sizer.appendChild(sizerChild.cloneNode(false));
}
// Re-use the element template for the remainder.
sizerChild.style[dimension] = (size - (numChildren * this.maxElementPixels)) + 'px';
this.sizer.appendChild(sizerChild);
}
};
/**
* If auto-shrinking is enabled, shrinks or unshrinks as appropriate.
* @private
* @param {number} size The new size.
*/
VirtualRepeatContainerController.prototype.autoShrink_ = function(size) {
var shrinkSize = Math.max(size, this.autoShrinkMin * this.repeater.getItemSize());
if (this.autoShrink && shrinkSize !== this.size) {
if (this.oldElementSize === null) {
this.oldElementSize = this.$element[0].style[this.getDimensionName_()];
}
var currentSize = this.originalSize || this.size;
if (!currentSize || shrinkSize < currentSize) {
if (!this.originalSize) {
this.originalSize = this.size;
}
// Now we update the containers size, because shrinking is enabled.
this.setSize_(shrinkSize);
} else if (this.originalSize !== null) {
// Set the size back to our initial size.
this.unsetSize_();
var _originalSize = this.originalSize;
this.originalSize = null;
// We determine the repeaters size again, if the original size was zero.
// The originalSize needs to be null, to be able to determine the size.
if (!_originalSize) this.updateSize();
// Apply the original size or the determined size back to the container, because
// it has been overwritten before, in the shrink block.
this.setSize_(_originalSize || this.size);
}
this.repeater.containerUpdated();
}
};
/**
* Sets the scrollHeight or scrollWidth. Called by the repeater based on
* its item count and item size.
* @param {number} itemsSize The total size of the items.
*/
VirtualRepeatContainerController.prototype.setScrollSize = function(itemsSize) {
var size = itemsSize + this.offsetSize;
if (this.scrollSize === size) return;
this.sizeScroller_(size);
this.autoShrink_(size);
this.scrollSize = size;
};
/** @return {number} The container's current scroll offset. */
VirtualRepeatContainerController.prototype.getScrollOffset = function() {
return this.scrollOffset;
};
/**
* Scrolls to a given scrollTop position.
* @param {number} position
*/
VirtualRepeatContainerController.prototype.scrollTo = function(position) {
this.scroller[this.isHorizontal() ? 'scrollLeft' : 'scrollTop'] = position;
this.handleScroll_();
};
/**
* Scrolls the item with the given index to the top of the scroll container.
* @param {number} index
*/
VirtualRepeatContainerController.prototype.scrollToIndex = function(index) {
var itemSize = this.repeater.getItemSize();
var itemsLength = this.repeater.itemsLength;
if(index > itemsLength) {
index = itemsLength - 1;
}
this.scrollTo(itemSize * index);
};
VirtualRepeatContainerController.prototype.resetScroll = function() {
this.scrollTo(0);
};
VirtualRepeatContainerController.prototype.handleScroll_ = function() {
var ltr = document.dir != 'rtl' && document.body.dir != 'rtl';
if(!ltr && !this.maxSize) {
this.scroller.scrollLeft = this.scrollSize;
this.maxSize = this.scroller.scrollLeft;
}
var offset = this.isHorizontal() ?
(ltr?this.scroller.scrollLeft : this.maxSize - this.scroller.scrollLeft)
: this.scroller.scrollTop;
if (offset === this.scrollOffset || offset > this.scrollSize - this.size) return;
var itemSize = this.repeater.getItemSize();
if (!itemSize) return;
var numItems = Math.max(0, Math.floor(offset / itemSize) - NUM_EXTRA);
var transform = (this.isHorizontal() ? 'translateX(' : 'translateY(') +
(!this.isHorizontal() || ltr ? (numItems * itemSize) : - (numItems * itemSize)) + 'px)';
this.scrollOffset = offset;
this.offsetter.style.webkitTransform = transform;
this.offsetter.style.transform = transform;
if (this.bindTopIndex) {
var topIndex = Math.floor(offset / itemSize);
if (topIndex !== this.topIndex && topIndex < this.repeater.getItemCount()) {
this.topIndex = topIndex;
this.bindTopIndex.assign(this.$scope, topIndex);
if (!this.$rootScope.$$phase) this.$scope.$digest();
}
}
this.repeater.containerUpdated();
};
VirtualRepeatContainerController.$inject = ['$$rAF', '$mdUtil', '$mdConstant', '$parse', '$rootScope', '$window', '$scope', '$element', '$attrs'];
/**
* @ngdoc directive
* @name mdVirtualRepeat
* @module material.components.virtualRepeat
* @restrict A
* @priority 1000
* @description
* `md-virtual-repeat` specifies an element to repeat using virtual scrolling.
*
* Virtual repeat is a limited substitute for ng-repeat that renders only
* enough DOM nodes to fill the container and recycling them as the user scrolls.
*
* Arrays, but not objects are supported for iteration.
* Track by, as alias, and (key, value) syntax are not supported.
*
* ### On-Demand Async Item Loading
*
* When using the `md-on-demand` attribute and loading some asynchronous data, the `getItemAtIndex` function will
* mostly return nothing.
*
* <hljs lang="js">
* DynamicItems.prototype.getItemAtIndex = function(index) {
* if (this.pages[index]) {
* return this.pages[index];
* } else {
* // This is an asynchronous action and does not return any value.
* this.loadPage(index);
* }
* };
* </hljs>
*
* This means that the VirtualRepeat will not have any value for the given index.<br/>
* After the data loading completed, the user expects the VirtualRepeat to recognize the change.
*
* To make sure that the VirtualRepeat properly detects any change, you need to run the operation
* in another digest.
*
* <hljs lang="js">
* DynamicItems.prototype.loadPage = function(index) {
* var self = this;
*
* // Trigger a new digest by using $timeout
* $timeout(function() {
* self.pages[index] = Data;
* });
* };
* </hljs>
*
* > <b>Note:</b> Please also review the
* <a ng-href="api/directive/mdVirtualRepeatContainer">VirtualRepeatContainer</a> documentation
* for more information.
*
* @usage
* <hljs lang="html">
* <md-virtual-repeat-container>
* <div md-virtual-repeat="i in items">Hello {{i}}!</div>
* </md-virtual-repeat-container>
*
* <md-virtual-repeat-container md-orient-horizontal>
* <div md-virtual-repeat="i in items" md-item-size="20">Hello {{i}}!</div>
* </md-virtual-repeat-container>
* </hljs>
*
* @param {number=} md-item-size The height or width of the repeated elements (which must be
* identical for each element). Optional. Will attempt to read the size from the dom if missing,
* but still assumes that all repeated nodes have same height or width.
* @param {string=} md-extra-name Evaluates to an additional name to which the current iterated item
* can be assigned on the repeated scope (needed for use in `md-autocomplete`).
* @param {boolean=} md-on-demand When present, treats the md-virtual-repeat argument as an object
* that can fetch rows rather than an array.
*
* **NOTE:** This object must implement the following interface with two (2) methods:
*
* - `getItemAtIndex: function(index) [object]` The item at that index or null if it is not yet
* loaded (it should start downloading the item in that case).
* - `getLength: function() [number]` The data length to which the repeater container
* should be sized. Ideally, when the count is known, this method should return it.
* Otherwise, return a higher number than the currently loaded items to produce an
* infinite-scroll behavior.
*/
function VirtualRepeatDirective($parse) {
return {
controller: VirtualRepeatController,
priority: 1000,
require: ['mdVirtualRepeat', '^^mdVirtualRepeatContainer'],
restrict: 'A',
terminal: true,
transclude: 'element',
compile: function VirtualRepeatCompile($element, $attrs) {
var expression = $attrs.mdVirtualRepeat;
var match = expression.match(/^\s*([\s\S]+?)\s+in\s+([\s\S]+?)\s*$/);
var repeatName = match[1];
var repeatListExpression = $parse(match[2]);
var extraName = $attrs.mdExtraName && $parse($attrs.mdExtraName);
return function VirtualRepeatLink($scope, $element, $attrs, ctrl, $transclude) {
ctrl[0].link_(ctrl[1], $transclude, repeatName, repeatListExpression, extraName);
};
}
};
}
VirtualRepeatDirective.$inject = ['$parse'];
/** @ngInject */
function VirtualRepeatController($scope, $element, $attrs, $browser, $document, $rootScope,
$$rAF, $mdUtil) {
this.$scope = $scope;
this.$element = $element;
this.$attrs = $attrs;
this.$browser = $browser;
this.$document = $document;
this.$mdUtil = $mdUtil;
this.$rootScope = $rootScope;
this.$$rAF = $$rAF;
/** @type {boolean} Whether we are in on-demand mode. */
this.onDemand = $mdUtil.parseAttributeBoolean($attrs.mdOnDemand);
/** @type {!Function} Backup reference to $browser.$$checkUrlChange */
this.browserCheckUrlChange = $browser.$$checkUrlChange;
/** @type {number} Most recent starting repeat index (based on scroll offset) */
this.newStartIndex = 0;
/** @type {number} Most recent ending repeat index (based on scroll offset) */
this.newEndIndex = 0;
/** @type {number} Most recent end visible index (based on scroll offset) */
this.newVisibleEnd = 0;
/** @type {number} Previous starting repeat index (based on scroll offset) */
this.startIndex = 0;
/** @type {number} Previous ending repeat index (based on scroll offset) */
this.endIndex = 0;
// TODO: measure width/height of first element from dom if not provided.
// getComputedStyle?
/** @type {?number} Height/width of repeated elements. */
this.itemSize = $scope.$eval($attrs.mdItemSize) || null;
/** @type {boolean} Whether this is the first time that items are rendered. */
this.isFirstRender = true;
/**
* @private {boolean} Whether the items in the list are already being updated. Used to prevent
* nested calls to virtualRepeatUpdate_.
*/
this.isVirtualRepeatUpdating_ = false;
/** @type {number} Most recently seen length of items. */
this.itemsLength = 0;
/**
* @type {!Function} Unwatch callback for item size (when md-items-size is
* not specified), or angular.noop otherwise.
*/
this.unwatchItemSize_ = angular.noop;
/**
* Presently rendered blocks by repeat index.
* @type {Object<number, !VirtualRepeatController.Block}
*/
this.blocks = {};
/** @type {Array<!VirtualRepeatController.Block>} A pool of presently unused blocks. */
this.pooledBlocks = [];
$scope.$on('$destroy', angular.bind(this, this.cleanupBlocks_));
}
/**
* An object representing a repeated item.
* @typedef {{element: !jqLite, new: boolean, scope: !angular.Scope}}
*/
VirtualRepeatController.Block;
/**
* Called at startup by the md-virtual-repeat postLink function.
* @param {!VirtualRepeatContainerController} container The container's controller.
* @param {!Function} transclude The repeated element's bound transclude function.
* @param {string} repeatName The left hand side of the repeat expression, indicating
* the name for each item in the array.
* @param {!Function} repeatListExpression A compiled expression based on the right hand side
* of the repeat expression. Points to the array to repeat over.
* @param {string|undefined} extraName The optional extra repeatName.
*/
VirtualRepeatController.prototype.link_ =
function(container, transclude, repeatName, repeatListExpression, extraName) {
this.container = container;
this.transclude = transclude;
this.repeatName = repeatName;
this.rawRepeatListExpression = repeatListExpression;
this.extraName = extraName;
this.sized = false;
this.repeatListExpression = angular.bind(this, this.repeatListExpression_);
this.container.register(this);
};
/** @private Cleans up unused blocks. */
VirtualRepeatController.prototype.cleanupBlocks_ = function() {
angular.forEach(this.pooledBlocks, function cleanupBlock(block) {
block.element.remove();
});
};
/** @private Attempts to set itemSize by measuring a repeated element in the dom */
VirtualRepeatController.prototype.readItemSize_ = function() {
if (this.itemSize) {
// itemSize was successfully read in a different asynchronous call.
return;
}
this.items = this.repeatListExpression(this.$scope);
this.parentNode = this.$element[0].parentNode;
var block = this.getBlock_(0);
if (!block.element[0].parentNode) {
this.parentNode.appendChild(block.element[0]);
}
this.itemSize = block.element[0][
this.container.isHorizontal() ? 'offsetWidth' : 'offsetHeight'] || null;
this.blocks[0] = block;
this.poolBlock_(0);
if (this.itemSize) {
this.containerUpdated();
}
};
/**
* Returns the user-specified repeat list, transforming it into an array-like
* object in the case of infinite scroll/dynamic load mode.
* @param {!angular.Scope} The scope.
* @return {!Array|!Object} An array or array-like object for iteration.
*/
VirtualRepeatController.prototype.repeatListExpression_ = function(scope) {
var repeatList = this.rawRepeatListExpression(scope);
if (this.onDemand && repeatList) {
var virtualList = new VirtualRepeatModelArrayLike(repeatList);
virtualList.$$includeIndexes(this.newStartIndex, this.newVisibleEnd);
return virtualList;
} else {
return repeatList;
}
};
/**
* Called by the container. Informs us that the containers scroll or size has
* changed.
*/
VirtualRepeatController.prototype.containerUpdated = function() {
// If itemSize is unknown, attempt to measure it.
if (!this.itemSize) {
// Make sure to clean up watchers if we can (see #8178)
if(this.unwatchItemSize_ && this.unwatchItemSize_ !== angular.noop){
this.unwatchItemSize_();
}
this.unwatchItemSize_ = this.$scope.$watchCollection(
this.repeatListExpression,
angular.bind(this, function(items) {
if (items && items.length) {
this.readItemSize_();
}
}));
if (!this.$rootScope.$$phase) this.$scope.$digest();
return;
} else if (!this.sized) {
this.items = this.repeatListExpression(this.$scope);
}
if (!this.sized) {
this.unwatchItemSize_();
this.sized = true;
this.$scope.$watchCollection(this.repeatListExpression,
angular.bind(this, function(items, oldItems) {
if (!this.isVirtualRepeatUpdating_) {
this.virtualRepeatUpdate_(items, oldItems);
}
}));
}
this.updateIndexes_();
if (this.newStartIndex !== this.startIndex ||
this.newEndIndex !== this.endIndex ||
this.container.getScrollOffset() > this.container.getScrollSize()) {
if (this.items instanceof VirtualRepeatModelArrayLike) {
this.items.$$includeIndexes(this.newStartIndex, this.newEndIndex);
}
this.virtualRepeatUpdate_(this.items, this.items);
}
};
/**
* Called by the container. Returns the size of a single repeated item.
* @return {?number} Size of a repeated item.
*/
VirtualRepeatController.prototype.getItemSize = function() {
return this.itemSize;
};
/**
* Called by the container. Returns the size of a single repeated item.
* @return {?number} Size of a repeated item.
*/
VirtualRepeatController.prototype.getItemCount = function() {
return this.itemsLength;
};
/**
* Updates the order and visible offset of repeated blocks in response to scrolling
* or items updates.
* @private
*/
VirtualRepeatController.prototype.virtualRepeatUpdate_ = function(items, oldItems) {
this.isVirtualRepeatUpdating_ = true;
var itemsLength = items && items.length || 0;
var lengthChanged = false;
// If the number of items shrank, keep the scroll position.
if (this.items && itemsLength < this.items.length && this.container.getScrollOffset() !== 0) {
this.items = items;
var previousScrollOffset = this.container.getScrollOffset();
this.container.resetScroll();
this.container.scrollTo(previousScrollOffset);
}
if (itemsLength !== this.itemsLength) {
lengthChanged = true;
this.itemsLength = itemsLength;
}
this.items = items;
if (items !== oldItems || lengthChanged) {
this.updateIndexes_();
}
this.parentNode = this.$element[0].parentNode;
if (lengthChanged) {
this.container.setScrollSize(itemsLength * this.itemSize);
}
// Detach and pool any blocks that are no longer in the viewport.
Object.keys(this.blocks).forEach(function(blockIndex) {
var index = parseInt(blockIndex, 10);
if (index < this.newStartIndex || index >= this.newEndIndex) {
this.poolBlock_(index);
}
}, this);
// Add needed blocks.
// For performance reasons, temporarily block browser url checks as we digest
// the restored block scopes ($$checkUrlChange reads window.location to
// check for changes and trigger route change, etc, which we don't need when
// trying to scroll at 60fps).
this.$browser.$$checkUrlChange = angular.noop;
var i, block,
newStartBlocks = [],
newEndBlocks = [];
// Collect blocks at the top.
for (i = this.newStartIndex; i < this.newEndIndex && this.blocks[i] == null; i++) {
block = this.getBlock_(i);
this.updateBlock_(block, i);
newStartBlocks.push(block);
}
// Update blocks that are already rendered.
for (; this.blocks[i] != null; i++) {
this.updateBlock_(this.blocks[i], i);
}
var maxIndex = i - 1;
// Collect blocks at the end.
for (; i < this.newEndIndex; i++) {
block = this.getBlock_(i);
this.updateBlock_(block, i);
newEndBlocks.push(block);
}
// Attach collected blocks to the document.
if (newStartBlocks.length) {
this.parentNode.insertBefore(
this.domFragmentFromBlocks_(newStartBlocks),
this.$element[0].nextSibling);
}
if (newEndBlocks.length) {
this.parentNode.insertBefore(
this.domFragmentFromBlocks_(newEndBlocks),
this.blocks[maxIndex] && this.blocks[maxIndex].element[0].nextSibling);
}
// Restore $$checkUrlChange.
this.$browser.$$checkUrlChange = this.browserCheckUrlChange;
this.startIndex = this.newStartIndex;
this.endIndex = this.newEndIndex;
if (this.isFirstRender) {
this.isFirstRender = false;
var firstRenderStartIndex = this.$attrs.mdStartIndex ?
this.$scope.$eval(this.$attrs.mdStartIndex) :
this.container.topIndex;
// The first call to virtualRepeatUpdate_ may not be when the virtual repeater is ready.
// Introduce a slight delay so that the update happens when it is actually ready.