Which plugin (npm) to use for localization in NativeScript and Angular?
nativescript-localize implements the native way of localizing iOS / Android apps.
tns plugin add nativescript-localize
If you like to find any plugins, you can simply do a search at https://market.nativescript.org/ Checkout the number downloads / recent releases to understand the popularity / stability of the plugin.
Note: At present this plugin doesn't support switching the language within your app, it always picks up the default language of the device which is more generic way of handling localization with mobile apps.
If you prefer to control the language selection within your app, you may have to go with any angular specific plugins to manage your language.