change
<widget id="
io.ionic.starter" version="0.0.1" xmlns="http://www.w3.org/ns/widgets" xmlns:cdv="http://cordova.apache.org/ns/1.0">
to
<widget id="
com.ieeess.slsywc17_mobile_app" version="0.0.1" xmlns="http://www.w3.org/ns/widgets" xmlns:cdv="http://cordova.apache.org/ns/1.0">
run
ionic cordova plugin add cordova-plugin-facebook4 --variable APP_ID="142512796409901" --variable APP_NAME="slsywc17-mobile-app"
npm install --save @ionic-native/facebook
ionic cordova platform add android
ionic cordova platform add ios
ionic cordova platform add browser
ionic cordova prepare
ionic cordova run browser -l