如何从ionic3迁移到ionic2以及如何从ionic2迁移回ionic3

Question

I want to know how to exchange between ionic 3 and 2 or 2 to 3 with keep same project

im use WINDOWS. in the first time, I install

npm install -g ionic Cordova

and for starting a new project i insert like following docs in ionicframework.com :

ionic start [myproject] blank

and

 cd [myproject]
 ionic serve

i don't know what the version ionic was installed? is the latest version by default or what? because of this article here : https://www.joshmorony.com/using-http-to-fetch-remote-data-from-a-server-in-ionic-2/

tell should install v2 in the first time and then we want to move to 3 !!

and I want to know how can moving between the version 2>>3 or 3>>2 without any crash. and I'm afraid if I'm using v3 by default and give something wrong while coding

plizzz someone explain carefully my issue

Answer 1

what you can do is to use a node version manager or nvm for short, which would let you handle different versions of node. By having different versions of node you can have ionic 3 on node XX version and ionic 2 in a different one.

since you are using windows you can use this one .

Answer 2

You can type in your console 'ionic info' and then you will see all info from your project. Sample output, from my environment:

global packages:

    @ionic/cli-utils : 1.4.0
    Cordova CLI      : 6.3.1 
    Ionic CLI        : 3.4.0

local packages:

    @ionic/app-scripts              : 1.3.7
    @ionic/cli-plugin-cordova       : 1.4.0
    @ionic/cli-plugin-ionic-angular : 1.3.1
    Cordova Platforms               : android 6.1.2 browser 4.1.0
    Ionic Framework                 : ionic-angular 3.5.0

System:

    Node       : v7.4.0
    OS         : Linux 4.4
    Xcode      : not installed
    ios-deploy : not installed
    ios-sim    : not installed
    npm        : 5.0.3 

You have to pay attention that there are differences between what is installed globally and what is local. Globally you should have ionic-cli, which is the command line tool used to manage Ionics' project (either 1, 2, or 3).

The version of the framework you are using is the Ionic Framework, installed locally, and managed by npm (via package.json, the package is called 'ionic-framework'). So, do change dependencies, you should only change the package.json from your project. You must pay attention, too, that each ionic-framework version has its own dependencies versions, specially from @angular (example: ionic-framework v2 uses angular2, ionic-framework v3 uses angular4).