I am getting WL.JSONStore is undefined error in mobile browser simulator while I am trying to use JSONStore in my mobile application.I am using IBM mobilefirst (version 8.0.0-2017091111). 
function wlCommonInit(){
WL.JSONStore.init(collections, options).then(function () {
alert("intialized successfully");
}).fail(function (errorObject) {
alert("failed to initialize collection\n"+ JSON.stringify(errorObject));
});
document.getElementById("btn_submit").addEventListener("click", onSubmit, false);
}
function onSubmit(){
var collectionName="people";
var data={firstName:$('#first').val(),middleName:$('#middle').val(),lastName:$('#last').val()};
WL.JSONStore.get(collectionName).add(data, options).then(function () {
alert("added data successfully");
}).fail(function (error) {
});
}
See more: https://mobilefirstplatform.ibmcloud.com/tutorials/en/foundation/8.0/application-development/jsonstore/cordova/#adding-jsonstore
https://www.npmjs.com/package/cordova-plugin-mfp-jsonstore