Update a route based on the battery capacity

Extending or limiting the battery capacity determines whether the routing will be conservative or aggressive. To make sure a charger or destination can be reached we advise to remain within the boundaries of -20% and +20% of the battery capacity.

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Requirements

Chargetrip API key - to plot routes outside this region
Mapbox API key - to display the map
URQL - a lightweight graphQL client

Steps to take

Plotting a route based on battery capacity starts by executing the newRoute mutation. This mutation requires information about the car, origin and destination. To support changing the battery capacity, the ev.battery.capacity argument needs to be treated as a variable. After the mutation is finished executing a route id will be returned.
This id can be used to request route updates through the routeUpdatedById subscription. This subscription receives dynamic updates.
After the subscription returns done as status, the polyline and legs fields will be available. These can be used to display the route and charge stations on the map. Additional data such as distance, duration and consumption are also available.
Now the ev.battery.capacity will be tied to a slider in the UI. Every time the slider gets updated, a new route will be generated and displayed to show the impact.

Next steps

Of course a car is not always at the same battery percentage. So apart from adjusting the battery capacity, the current state of charge can be set. How this is done, is explained in our next example.

          import { SubscriptionClient } from 'subscriptions-transport-ws';import { createClient, createRequest, defaultExchanges, subscriptionExchange } from '@urql/core';import { createRoute, routeUpdate } from './queries';import { pipe, subscribe } from 'wonka'; /** * For the purpose of this example we use urql - lightweights GraphQL client. * To establish a connection with Chargetrip GraphQL API you need to have an API key. * The key in this example is a public one and gives access only to a part of our extensive database. * You need a registered `x-client-id` to access the full database. * Read more about authorisation in our documentation (https://docs.chargetrip.com/#authorisation). */const headers = {  //Replace this x-client-id and app-id with your own to get access to more cars  'x-client-id': '5ed1175bad06853b3aa1e492',  'x-app-id': '623998b2c35130073829b2d2',}; const subscriptionClient = new SubscriptionClient('wss://api.chargetrip.io/graphql', {  reconnect: true,  connectionParams: headers,}); const client = createClient({  url: 'https://api.chargetrip.io/graphql',  fetchOptions: {    method: 'POST',    headers,  },  exchanges: [    ...defaultExchanges,    subscriptionExchange({      forwardSubscription(operation) {        return subscriptionClient.request(operation);      },    }),  ],}); /** * The function that makes a route request to the Chargetrip API with the customized battery capacity. * @param { number } capacity - The current battery capacity * @param { function } callback - As soon as our asynchronous call is finished we do a callback to update our UI. */export const getRoute = (capacity, callback) => {  client    .mutation(createRoute, { capacity: capacity })    .toPromise()    .then(response => {      const routeId = response.data.newRoute;       const { unsubscribe } = pipe(        client.executeSubscription(createRequest(routeUpdate, { id: routeId })),        subscribe(result => {          const { status, route } = result.data?.routeUpdatedById;           // You can keep listening to the route changes to update route information.          // For this example we want to only draw the initial route.          if (status === 'done' && route) {            unsubscribe();            callback(route);          } else if (status === 'not_found') {            callback();          }        }),      );    })    .catch(error => console.log(error));};