angular in the life cycle:
When the component is loaded, the order lifecycle functions:
00 - constructor: constructor is executed first, generally used to initialize variables, should not do other things
01 - ngOnChanges: execution when the input value is bound property changes, the father and son pass the value of the components automatically when called. Attribute value change is not input, the function is not performed
02 - ngOnInit: executes initialization commands and components performed only once. Usually the request data on the function
03 - ngDoCheck (): executed when the property value is bound to change, such as two-way data binding, change attributes, which will trigger
04 - ngAfterContentInit (): After the content projected onto the component calls executed only once
05 - ngAfterContentChecked (): projection component content calls after the change occurs, is performed after ngDoCheck ()
06 - ngAferViewInit (): component view and a rear view of the sub-loading completion call, DOM operation in the process
07 - ngAfterViewChecked (): Components and child views changed after the call, each ngAfterViewInit () or ngAfterContentInit call (after)
08 - ngOnDestroy (): the destruction of the component calls