javascript - why does the custom component run before the page is created in ionic 2? -


i implement custom component in ionic project , followed this guide realize it.

on page, instantiate variable pass component

export class newsegmentpage {  name: any;  constructor(public navctrl: navcontroller, public navparams: navparams) { this.name = "hello";       }

and in template

... <ion-content>   <slider [name]="name"></slider> </ion-content>

now create component

<ion-item>   <ion-range dualknobs="true" pin="true" [(ngmodel)]="structure"></ion-range> </ion-item>

and retrieve data pass variable @input

@input("coordinates") activity; structure: = { lower: 33, upper: 60 };  constructor() {    console.log(this.activity); }

but this.activity variable undefined.

in addition, in google console saw component created before page , that's why fails pass data. but, how behave that?

the execution right wrong retrieve this.activity variable in constructor. off of constructor variable instantiated. 

ngafterviewinit() {    console.log(this.activity);     }

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