addon/core.js
function changedKeys(props, newProps) {
  return Object.keys(props).filter(key => {
    return props[key] !== newProps[key];
  });
}
function changedKeys(props, newProps) {
  return Object.keys(props).filter(key => {
    return props[key] !== newProps[key];
  });
}
function changedKeys ( props , newProps ) { return Object . keys ( props ) . filter ( key => { return props [ key ] !== newProps [ key ] ; } ) ; }
Returns a list of keys that have different values between the two objects.

@method changedKeys
@return {Array} keys that have changed
@private
Returns a list of keys that have different values between the two objects .