Client Stack Example

Create

Let's say our app want's to create one container object and add two objects inside of it.

This can be done as follows:

const container1 = await this.evees.createEvee();
const child1 = await this.evees.createChild();
const child2 = await this.evees.createChild();

const container2 = await this.evees.createEvee();
await this.evees.addExistingChild(container2, child1);

These changes will create the perspectives on the top client (in memory).

So the data would look like this:

• 4 new perspectives created on the OnMemory ClientMutation. Container 1 c1 has k1 and k2 as childrent, while c2 has k1 as a child. The ClientMutation essentially stores the head of each perspective, which are marked in blue.
• 8 new entities stored in the EntityCache of the EntityResolver. 4 entities represent the head commits and the other 4 are the data entities, which are included inside the commit object as a link.

Calling the diff() method on the ClientMutation will return an EveesMutation object with 4 elements in the newPerspectives array. Each element will have the perspective payload, and the update details with the corresponding head.

const diff = await this.evees.client.diff();

/**
 * diff = {
 *   newPerspectives: [
 *     {
 *       perspective: {
 *         hash: c1,
 *         object: ...
 *       },
 *       update: {
 *         details: {
 *           headId: hc1
 *         }
 *       }
 *     },
 *     ...
 *     A total of 4 perspectives would be listed in the "newPerspectives" array.
 *     ...
 *   ]
 * }/*

Flush

Let's now assume we want to persist these changes in our remotes. We can do this by calling the flush() command. At this point these changes are removed from the ClientMutation layer and sent to the ClientRemote as a single EveesMutation object.

The data would then look like this:

Update

Now let's consider the case where the app want's to update the content of a perspective, let's say add a new child. It can simply do it by calling

const child3 = await this.evees.addNewChild(c1, {});

Because we have not flushed it, this operation is applied to the top layer ClientMutation only, which stores the changes on memory. Two things are done when adding a new child, a new perspective is created, and the parent is updated to add that new perspective as a child. The ClientMutation stored on the onMemory Client is then

const diff = await this.evees.client.diff();

/**
 * diff = {
 *   newPerspectives: [
 *     {
 *       perspective: {
 *         hash: k3,
 *         object: ...
 *       },
 *       update: {
 *         details: {
 *           headId: hk1
 *         }
 *       }
 *     },
 *   ],
 *   updates: [
 *     {
 *       perspectiveId: c1,
 *       details: {
*          headId: hc1-2
 *       }
 *     }
 *   ]
 * }/*

The data would then look like this: