Build Client API

• Generates hooks to make API calls based on a passed in Api Options
• Allows defining a simple model for a group of endpoints to generate the hooks

Api Options

• The Options are split into two parts queries and mutations
• With each, a route-model should be defined for each individual endpoint

Query Endpoints

• All query endpoints should be defined under queries property
• All endpoints defined within the queries property will make a get request
  • The get request is hard coded, and currently can not be changed

Mutation Endpoints

• All mutation endpoints should be defined under mutations property
• Mutation endpoints can make request of the following types
  • post, patch, put, delete
• Other than the delete methods, each mutation hook accepts a payload object
  • The payload object should include the body content of the request

Route model

• Both queries and mutations are defined by a route-model
• A route-model is defined by the following properties
  • method - The HTTP verb to use when making the request
  • route - The request url path name, i.e. /strategies/23/pillars
    • Can be a string or function
    • As a function, it will be called with the Hook Options passed to the calling hook
  • payload - Used as the body of the request for mutations only
  • onError - Callback called when an error is thrown durning the request
  • onSuccess - Callback called when a request is successful
  • onBefore - Callback called before a request is made
    • Useful for validating the payload of a mutation
    • If this callback throws an error, it will be caught
    • All caught errors will skip the request and be passed to the onError callback as a NetworkError
    • If this callback returns false, a generic error will be throw
    • The callback should return anything other than false to not throw an error
  • onUnMount - Callback called when a get request is made and the calling Component unmounts
    • Useful for cleaning up local state when desired

Api Options Example

const endpointHooks = buildApiClient({
  queries: {
    getAll: {
      // Will use 'get' regardless of what is defined here
      method: `get`,
      route: `/api/endpoint/pathname`,
      // Called when the parent component is unmounted
      onUnMount: () => {},
      // Called when a error is thrown durning a request
      // This includes errors in the `onBefore` callback
      onError: (error: any) => {},
      // Called when a request is successful
      onSuccess: <T>(result: T) => {},
    },
    get: {
      method: `get`,
      // The route as a function
      route: (data: HookMethodOptions) => `/endpoint/${data.payload.id}`,
      // Callback methods are not required
    },
  },
  mutations: {
    create: {
      // Can be any mutation HTTP verb - post, put, patch, delete
      method: 'post',
      // Accepts all the same arguments as queries
      // The `onUnMount` callback is ignored for all mutations
    },
  },
})

Api Client Hooks

• The buildApiClient method returns an object with properties matching the passed in Api Options object
• It is split into two parts queries and mutations same as the Api Options object
• Within both the queries and mutations properties are React Hook functions
  • These are real hooks and follow all the same rules as normal react hooks
  • They must be called within the body of a Function Component
  • They can NOT be called conditionally
• These hooks use closures
  • This allows them to maintain access to the Api Options object originally passed when they were being built
  • This allows defining properties and logic for an API request in a single location, and then reusing it where needed
• It is recommended to export the hooks built from the buildApiClient method using the use prefix
  • This is the same pattern used by react, let others know it is a hook, and not regular function
  • For example:
    • If I have a hook called getItem
    • I would export it as useItem

Hooks Example

• Given the same endpointHooks as defined in the above example
• The buildApiClient method would return the following object

const endpointHooks = {
  queries: {
    // Contains references to the queries.get route-model above
    get: useQuery,
    // Contains references to the queries.getAll route-model above
    getAll: useQuery,
  }
  mutations: {
    // Contains references to the mutations.create route-model above
    create: useMutation,
  }
}

Query Hooks

• The useQuery hook is built internally when the buildApiClient method is called
• All route-model defined in the queries property of the Api Options will be converted into a useQuery hook
• These hooks can be access from the queries property of the response of the buildApiClient method call
  • For example:
    • Given I pass the following Api Options object => { queries: { get: { ...<route-model> }}}
    • I can access the hook for the get hook in the response from buildApiClient at response.queries.get
• Unlike the mutation hooks, the request made by the useQuery hook are initiated immediately

Query Hook Options

• This hook accepts an options object with the similar properties as in the initial Api Options object route-model
• Properties in this object will impact original route-model properties in the following ways
  • payload => Is merged with the original payload
  • onBefore | onSuccess | onError | onUnMount => Will overwrite the original method
    • These methods can be defined inline without the need for memoization
    • The onUnMount callback exists for mutations only
  • route => When route is a function, the options object will be passed as the first argument
• Aside from the above properties, the options object has the following
  • enabled - If false, the API call will be by-passed
  • cache - If true, the response will be cached. Future calls will use the cached response until cleared
    • Cache exists for queries only
  • apiOptions - Object passed on to the axios client
    • mapper? - (item: Record<string, any>[]) => any[]
    • config? - AxiosRequestConfig from the axios library

Query Hook Response

• The hook response contains the following properties
  • loading - Is true when the API request is in flight
  • data - The API client response. Is undefined until a successful API call is made
  • error - Network Error response. Is undefined until an error is thrown, or the API call fails
  • clearCache - Clears the cache for the specific API call
  • getCache - Returns the cached response for the specific API call

Mutation Hooks

• The useMutation hook is built internally when the buildApiClient method is called
• All route-model defined in the mutations property of the Api Options will be converted into a useMutation hook
• These hooks can be access from the mutations property of the response of the buildApiClient method call
  • For example:
    • Given I pass the following Api Options object => { mutations: { post: { ...<route-model> }}}
    • I can access the hook for the post hook in the response from buildApiClient at response.mutations.post
• Unlike the query hooks, the request made by the mutation hook are NOT immediately initiated
  • Instead they return a useMutation hook that must be called to initiate the API call

Mutation Hook Options

• This hook accepts an options object with the similar properties as in the initial Api Options object route-model
• Properties in this object will impact original route-model properties in the following ways
  • payload => Is merged with the original payload
  • onBefore | onSuccess | onError | onUnMount => Will overwrite the original method
    • These methods can be defined inline without the need for memoization
    • The onUnMount callback exists for mutations only
  • route => When route is a function, the options object will be passed as the first argument
• Aside from the above properties, the options object has the following
  • enabled - If false, the API call will be by-passed
  • apiOptions - Object passed on to the axios client
    • mapper? - (item: Record<string, any>[]) => any[]
    • config? - AxiosRequestConfig from the axios library

Mutation Hook Response

• The hook response contains the following properties
  • loading - Is true when the API request is in flight
  • data - The API client response. Is undefined until a successful API call is made
  • error - Network Error response. Is undefined until an error is thrown, or the API call fails
  • useMutate - Hook that will make the actual API request
    • Mutation hooks are not called immediately in the way that query hooks are
    • Instead this useMutation hook is returned and that must be called to initiate the API call