Mutator

The mutator allows to interfere with the query before it is built.

Method Signature

mutator?: (qb: QueryBuilder<T>) => QueryBuilder<T>;

Returns

The mutator method returns the QueryBuilder instance.

Examples

Add a where clause to the query.

const query = createQuery<Post>('/api/posts', {
  mutator((qb) => {
    return qb.where('id', '>', 1);
  }).select(['id', 'title']);
});

Basically, it breaks the chain for you and lets you be more dynamic on building queries.

Let's take a more complex example:

1. From the defaults page we can take this:

export function queryfi<T extends Record<string, any>>(
  basePath: string,
  options?: QueryBuilderOptions
): QueryBuilder<T> {
  return new QueryBuilder<T>(basePath, options);
}

2. Create a buildQuery method that will be used to build your queries:

import { queryfi } from "@/lib/queryfi";
import { QueryBuilder } from "queryfi";

export const buildQuery = <T>({
  mutate,
  getter,
  path,
}: {
  mutate?: (qb: QueryBuilder<T>) => QueryBuilder<T>;
  getter?: "get" | "first" | "build" | "count";
  path: string | number;
}) => {
  return queryfi<T>(`/api/{api_version}/${path ?? ""}`)
    .mutator((qb) => (mutate ? mutate(qb) : qb))
    [getter]();
};

3. Use it to fetch your data:

export async function getMyData<T>( // we use a generic in case you want an array or a single object.
    mutate?: (qb: QueryBuilder<T>) => QueryBuilder<T>,
    getter?: "get" | "first" | "build" | "count"
    ) {
    const url = buildQuery<T>({
        path: "user",
        getter: getter ?? "get" // get gets an array, first only one object,
        mutate(qb) {
          if (mutate) {
            return mutate(qb);
          }
          return qb;
        },
      });

      const { data } = await fetchClient<T>({
        url,
      });

      return data;
}

The above code returns an array of users.

Now we can reuse this piece of code to fetch the users in any manner we want.

const data = await getMyData<IUser[]>((qb) => {
  return qb.where([
    ['name', 'like', '%doe%'],
    ['email', 'like', '%gmail%'],
  ]).select(['email', 'name', 'id'])
  ;
}, 'get');