%PDF-
%PDF-
Mini Shell
Mini Shell
define('widget/loaded-range', function() {
'use strict';
/**
* A widget for tracking which pages of items have been loaded.
*/
function LoadedRange(capacity) {
//assumption: only a contiguous range of lines will ever be loaded.
this.start = undefined;
this.nextPageStart = undefined;
this._reachedStart = false;
this._reachedEnd = false;
this._reachedCapacity = false;
this._capacity = capacity || Infinity;
}
LoadedRange.prototype.isEmpty = function() {
return this.start === undefined;
};
LoadedRange.prototype.isBeforeStart = function(item) {
return item < this.start;
};
LoadedRange.prototype.isAfterNextPageStart = function(item) {
return item > this.nextPageStart;
};
LoadedRange.prototype.isLoaded = function(item) {
return !(this.isEmpty() || this.isBeforeStart(item) || this.isAfterNextPageStart(item));
};
LoadedRange.prototype.getAttachmentMethod = function(start, size) {
return this.isEmpty() ?
'html' :
this.isBeforeStart(start) ?
'prepend' :
'append';
};
LoadedRange.prototype.add = function(start, size, isLastPage, nextPageStart) {
var isEmpty = this.isEmpty();
nextPageStart = nextPageStart || (start + size);
if (isEmpty || this.isBeforeStart(start)) {
this.start = start;
}
if (isEmpty || this.isAfterNextPageStart(nextPageStart)) {
this.nextPageStart = nextPageStart;
}
this._reachedStart = this._reachedStart || start <= 0;
var reachedEnd = this._reachedEnd = this._reachedEnd || isLastPage;
if (!reachedEnd && this.nextPageStart >= this._capacity) {
this._reachedCapacity = this._reachedEnd = true;
}
return this;
};
LoadedRange.prototype.reachedStart = function() { return this._reachedStart; };
LoadedRange.prototype.reachedEnd = function() { return this._reachedEnd; };
LoadedRange.prototype.reachedCapacity = function() { return this._reachedCapacity; };
LoadedRange.prototype.pageBefore = function(pageSize) {
if (this.reachedStart()) return null;
var start = Math.max(0, this.start - pageSize);
return {
start : start,
limit : this.start - start
};
};
LoadedRange.prototype.pageAfter = function(pageSize) {
if (this.reachedEnd()) return null;
return {
start : this.nextPageStart,
limit : pageSize
};
};
return LoadedRange;
});
Zerion Mini Shell 1.0