Lazy Query in RTK Query

Understanding `useLazyGetCustomerNameListQuery` in Redux Toolkit Query

useLazyGetCustomerNameListQuery is a special hook generated by Redux Toolkit Query (RTK Query) for the getCustomerNameList query endpoint in your API. Unlike regular query hooks, it allows you to execute the query on demand, rather than automatically when the component renders.

This is particularly useful in scenarios where you don't want the query to run until a specific user action (e.g., clicking a button) triggers it.

How It Works

The hook returns an array with two elements:

A function to trigger the query (trigger).
An object containing the query state (e.g., data, isLoading, error).

Hook Usage

Here’s how you can use useLazyGetCustomerNameListQuery correctly:

const [trigger, { data, error, isLoading }] = useLazyGetCustomerNameListQuery();

Explanation of the Hook's API:

trigger(queryParams): A function you call to execute the query with optional parameters (queryParams).
data: Contains the result of the query once it completes.
isLoading: A boolean indicating if the query is currently in progress.
error: Provides details if the query fails.

Example: Using `useLazyGetCustomerNameListQuery`

import React from 'react';
import { useLazyGetCustomerNameListQuery } from './apiSlice';

const CustomerNameList = () => {
  const [trigger, { data, error, isLoading }] = useLazyGetCustomerNameListQuery();

  const handleFetchNames = () => {
    trigger({ /* optional query params */ });
  };

  return (
    <div>
      <button onClick={handleFetchNames}>Fetch Customer Names</button>

      {isLoading && <p>Loading...</p>}
      {error && <p>Error: {error.message}</p>}
      {data && (
        <ul>
          {data.map((name, index) => (
            <li key={index}>{name}</li>
          ))}
        </ul>
      )}
    </div>
  );
};

export default CustomerNameList;

Key Points to Remember:

Lazy Execution: The query does not execute automatically. You must call the trigger function to initiate it.
Flexible Parameters: You can pass parameters to the trigger function to customize the API request dynamically.
State Management: The hook manages loading, error, and response states for you.

This example demonstrates the correct way to use a lazy query hook. It ensures the query is executed only when required, avoiding unnecessary API calls.

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This version explicitly addresses the key aspects of useLazyGetCustomerNameListQuery and avoids the pitfalls of the original example by accurately showcasing lazy execution.

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Disclaimer

This content has been generated with the assistance of AI. While I strive for accuracy and quality, please verify critical information independently.

Top comments (2)

Nick Pantelidis • Dec 13 '24

The example is completely wrong because lazy query has to be called when you want and not automatically as in the example that you give. You should be ashamed to upload content that misleads people that may not be so familiar with RTK Query.