META-INF.assets.rjzjh.echarts.src.data.DataDiffer.js Maven / Gradle / Ivy
define(function(require) {
'use strict';
function defaultKeyGetter(item) {
return item;
}
function DataDiffer(oldArr, newArr, oldKeyGetter, newKeyGetter) {
this._old = oldArr;
this._new = newArr;
this._oldKeyGetter = oldKeyGetter || defaultKeyGetter;
this._newKeyGetter = newKeyGetter || defaultKeyGetter;
}
DataDiffer.prototype = {
constructor: DataDiffer,
/**
* Callback function when add a data
*/
add: function (func) {
this._add = func;
return this;
},
/**
* Callback function when update a data
*/
update: function (func) {
this._update = func;
return this;
},
/**
* Callback function when remove a data
*/
remove: function (func) {
this._remove = func;
return this;
},
execute: function () {
var oldArr = this._old;
var newArr = this._new;
var oldKeyGetter = this._oldKeyGetter;
var newKeyGetter = this._newKeyGetter;
var oldDataIndexMap = {};
var newDataIndexMap = {};
var i;
initIndexMap(oldArr, oldDataIndexMap, oldKeyGetter);
initIndexMap(newArr, newDataIndexMap, newKeyGetter);
// Travel by inverted order to make sure order consistency
// when duplicate keys exists (consider newDataIndex.pop() below).
// For performance consideration, these code below do not look neat.
for (i = 0; i < oldArr.length; i++) {
var key = oldKeyGetter(oldArr[i], i);
var idx = newDataIndexMap[key];
// idx can never be empty array here. see 'set null' logic below.
if (idx != null) {
// Consider there is duplicate key (for example, use dataItem.name as key).
// We should make sure every item in newArr and oldArr can be visited.
var len = idx.length;
if (len) {
len === 1 && (newDataIndexMap[key] = null);
idx = idx.unshift();
}
else {
newDataIndexMap[key] = null;
}
this._update && this._update(idx, i);
}
else {
this._remove && this._remove(i);
}
}
for (var key in newDataIndexMap) {
if (newDataIndexMap.hasOwnProperty(key)) {
var idx = newDataIndexMap[key];
if (idx == null) {
continue;
}
// idx can never be empty array here. see 'set null' logic above.
if (!idx.length) {
this._add && this._add(idx);
}
else {
for (var i = 0, len = idx.length; i < len; i++) {
this._add && this._add(idx[i]);
}
}
}
}
}
};
function initIndexMap(arr, map, keyGetter) {
for (var i = 0; i < arr.length; i++) {
var key = keyGetter(arr[i], i);
var existence = map[key];
if (existence == null) {
map[key] = i;
}
else {
if (!existence.length) {
map[key] = existence = [existence];
}
existence.push(i);
}
}
}
return DataDiffer;
});