Architectural ConsiderationsFolder OrganizationUnderstanding the Class SystemUsing xtypesOverview of the Class LibraryFoundation UtilitiesExtemptyFnversionapplication()bind()clone()create(), define(), and widget()decode() and encode()defer()destroy()each()getBody(), getDoc(), and getHead()getClass() and getClassName()getCmp() and getStore()id()isArray(), isBoolean(), isDate(), isDefined(), isElement(), and othersiterate()namespace()typeOf()Ext.Arrayclean()contains()difference()erase()every() and some()filter()flatten()from()include()indexOf()insert()intersect()map() and pluck()max(), mean(), min(), and sum()merge() and union()remove()replace() and splice()slice()sort()toArray()unique()Ext.ComponentQueryComponent Query SyntaxExt.DateExtrasadd()between()clearTime()format()getDayOfYear(), getWeekOfYear(), isLeapYear()getDaysInMonth(), getFirstDateOfMonth(), getFirstDayOfMonth(), getLastDateOfMonth(), getLastDayOfMonth()getElapsed()getGMTOffset(), getTimezone(), isDST()getMonthNumber(), getShortDayName(), getShortMonthName(), getSuffix()isValid()parse()Ext.DomHelper and Ext.DomQueryselect() and selectNode()append(), insertBefore(), insertAfter(), overwrite(), insertHtml()Ext.env.FeatureExt.FunctioncreateDelayed()createInterceptor()createSequence()createThrottled()defer()flexSetter()pass()Ext.JSONExt.Loggerdeprecate(), error(), log(), and warn()Ext.Numberconstrain()from()snap()toFixed()Ext.Objecteach()fromQueryString() and toQueryString()getKey(), getKeys(), getSize(), getValues()merge()toQueryObjects()Ext.Stringcapitalize()ellipsis()escape() and escapeRegex()format()htmlDecode() and htmlEncode()leftPad(), repeat(), and trim()toggle()urlAppend()Ext.VersionExt.mixin.ObservableExt.util.DelayedTaskExt.util.HashMapadd(), clear(), remove(), removeByKey(), replace()contains(), containsKey()each()get(), getCount(), getKeys(), getValues()Ext.util.InflectorisTransnumeral()ordinalize()pluralize(), singularize()Conclusion