Improvements for client-side routing with OPE

// Listen to the `beta/epiReady` event to update the `context` property.
window.addEventListener('load', () => {
    // Expect `epi` to be there after the `load` event. If it's not then we're
    // not in any editing context.
    if (!window.epi) {
        return;
    }
 
    function logContext() {
        // The event only has `isEditable`, but the epi object has both properties.
        var context = { 
            inEditMode: window.epi.beta.inEditMode,
            isEditable: window.epi.beta.isEditable
        };
        console.log(context);
    }
 
    // Check for beta and that ready is an actual true value (not just truthy).
    if (window.epi.beta && window.epi.beta.ready === true) {
        // `beta/epiReady` already fired, so just grab the `isEditable` from the window.epi object.
        logContext();
    } else if (window.epi.subscribe) { // The subscribe method won't be available in View mode, so we need to check for it.
        // If the `beta/epiReady` event hasn't happened yet, then subscribe to it.
        window.epi.subscribe('beta/epiReady', () => logContext());
    }
});