react dropdown component

　　React component life cycle-function execution order in the initialization phase

First, the demandWhen there is a value for the Pass property name, the hello "name" is displayed, otherwise the Hello WorldTwo, 4 ways of code implementation1. Through ternary operators　　2. Pass the variable　　3. Calling functions directly in the property　　4. Use and operation　　Iii. Results of operationAssigning values to react component properties through expressions and functions

Combining input streams then using scan -to-track the results are a common scenario when coding with streams. This lesson walks you through setting up the buttons and merging their input events together to build a streaming Counter Component.Const Counterstream = Componentfromstream ( = = = Createeventhandler (); = Createeventhandler (); return props$ switchmap ( = observable.merge ( oninc$.mapto (1), ondec$ . Mapto (-1) ) . Startwith (propos.valu

vargrandson =React.createclass ({handleselect:function ( event) {var s = event.target.value + "person"; this . Props.handleselect (s); }, render:function () {return ( "1px solid Red", margin:"10px"}}>{ This. Props.name}:Selectonchange={This.handleselect}> "male"> Men "female"> Women Select> ) }});varChild =React.createclass ({handleval:function (Event) { varv =Event. Target.value +"@china"; This . Props.handleval (v); }, Render:function () {return ( "1px

One. var Fancycheckbox = React.createclass ({render:function () {var fancyclass = this.props.checked?' fancychecked ': ' fancyunchecked '; Return ( Two. var Fancycheckbox = React.createclass ({render:function () {var {checked, ... other} = This.props;var Fancyclass = checked?' fancychecked ': ' fancyunchecked '; ' Other ' contains {OnClick:console.log} and not the Checked property return ( React Component