IONIC 2 Hide and Show textbox when ion-select is change - ionic-framework

Question

I want to hide and show the textbox when the ion-select(combobox) is change
For example I have : 1 and 2 in ion-select
If i choose 1 the textbox will hide and if i choose 2 the textbox will appear
Here is my current code:
.ts
onChange(membership){
if (this.membership = '1'){
this.value = 1; }
else if (this.membership = '2'){
this.value = ""; }
}
HTML
<ion-list>
<ion-item>
<ion-label>Register as</ion-label>
<ion-select [(ngModel)]="membership" (ionChange)="onChange(membership)">
<ion-option value="1">member</ion-option>
<ion-option value="2">nonmember</ion-option>
</ion-select>
</ion-item>
</ion-list>
this is the textbox that i want to hide
<ion-item [hidden]="!value">
<ion-label floating>Email Address</ion-label>
<ion-input type="text" name="email" ></ion-input>
</ion-item>
When I'm opening the application the textbox is hiding and when i select from the combobox the textbox is showing but when I select the other item in the combobox its not hiding anymore.

Answer 1

It is just a simple error in onChange method. You are assigning the value with =, so it always returns true and set this.value to 1. You have to use double equals to verify equality :
onChange(membership){
if (this.membership == '1') {
this.value = 1;
} else if (this.membership == '2'){
this.value = 0;
}
}