AsyncSource

AsyncSource is a stateful, reactive data source designed for managing asynchronous requests in modern JavaScript and TypeScript projects. It provides robust features for error handling, throttling, and caching, making it ideal for applications that require efficient data management.

Features

Stateful Management: Track the state of your requests, including (isLoading, isFetched, data).

Error Handling: Automatically manage errors with customizable handlers, ensuring a smooth user experience.

Debounce Control: Integrate built-in debouncing to manage rapid requests, preventing redundant calls and ensuring only the latest call is processed.

Cache Support: Cache responses locally with configurable storage options and expiration times, enhancing performance and reducing unnecessary network requests.

Automatic State Consistency: In cases of multiple calls, only the last call will be processed, maintaining data integrity and consistency.

Use Cases

• Connect AsyncSource to dynamic selects to efficiently handle user interactions and data fetching.
• Implement throttling and debouncing in applications that require real-time data updates without overwhelming the server.

Install

npm install --save async-source

Usage

// javascript
import AsyncSource from 'async-source';

const source = new AsyncSource(request);

async function loadItems() {
    await source.update(...requestParams);
    const response = source.data;
}

// typescript
import AsyncSource from 'async-source';

const source = new AsyncSource<RespnonsType>(request);

async function loadItems() {
    await source.update(...requestParams);
    const response = source.data;
}

Parameters

Parameter	Is required	Description
serviceMethod	true	Method that returns promise
errorHandler	false	Function that will be called in case of service method rejected
delay	false	delay in ms

Properties(reactive getters)

Property	Description	Type
data	Returns your method response	Your method response
isLoading	Returns true when request pending	Boolean
isFetch	Returns true after first load	Boolean

Methods

Method	Description	Params
update	Calls be request	Your method request params
push	Calls be request and handles success response	Success handler, Your method request params
updateIfEmpty	Calls be request in source if data is empty	Your method request params
updateOnce	Calls be request in source if data is empty and waits till other request resolved	Your method request params
updateImmediate	Calls be request in source ignoring debounce	Your method request params
clear	Set source data to initial state(null)	---

Usage with vue3(composition api)

<template>
    <ul v-loading="isLoading">
        <li v-for="item in items" :key="item.id">
            {{ item.name }}
        </li>
    </ul>
</template>

<script>
import AsyncSource from 'async-source';
import { computed, reactive } from 'vue';

export default {
    name: 'MyComponent',
    setup() {
        function errorHandler(error) {
            console.error(error);
        }

        const source = reactive(new AsyncSource(request, errorHandler, 300));

        source.update();

        const items = computed(() => source.data || []);
        const isLoading = computed(() => source.isLoading);
        
        return {
            items,
            isLoading
        };
    }
}

</script>

Usage with vue2(option api)

<template>
    <ul v-loading="isLoading">
        <li v-for="item in items" :key="item.id">
            {{ item.name }}
        </li>
    </ul>
</template>

<script>
import AsyncSource from 'async-source';

export default {
    name: 'MyComponent',
    data() {
        return {
            source: new AsyncSource(request, this.errorHandler, 300)
        }
    },
    computed: {
        items() {
            return this.source.data || [];
        },
        isLoading() {
            return this.source.isLoading;
        }
    },
    created() {
        this.source.update();
    },
    methods: {
        errorHandler(error) {
            console.error(error);
        }
    }
}

</script>

Cache

Global cache configuration

To apply global settings, use setConfig:

import AsyncSource from 'async-source';

AsyncSource.setConfig({
    cacheStorage: localStorage,               // or any custom sync/async storage
    cacheTime: 12 * 60 * 60 * 1000,           // cache for 12 hours
    cachePrefix: 'MyAppAsyncSource'            // optional prefix for cache keys
});

Instance-Level Configuration

Specify custom settings for each AsyncSource instance by passing an options object as the third parameter. This object can include both caching and debounce settings.

new AsyncSource<T>(
    serviceMethod: (...args: any[]) => Promise<T>,
    errorHandler?: (error: any) => void,
    configOrDelay?: number | ConfigOptions
)

Parameter	Required	Description
serviceMethod	Yes	Method that returns a promise.
errorHandler	No	Function to handle errors in the service method.
configOrDelay	No	Debounce delay (in ms) or an object with config options.

ConfigOptions Interface

If using a configuration object for configOrDelay, it can include:

interface ConfigOptions {
    debounceTime?: number;        // Delay before request execution (in milliseconds)
    requestCacheKey?: string | (() => string);     // Request cache key (required for enable cache)
    cacheTime?: number;           // Cache expiration in milliseconds
    cacheStorage?: CacheStorage;  // Storage (e.g., localStorage, sessionStorage, indexDB)
    isUpdateCache?: boolean;      // Refetch cache every time when true.
}

Option	Type	Default	Description
debounceTime	number	300	Delay before request execution (in milliseconds).
requestCacheKey	string | (() => string)		Request cache key (required for enabling cache).
cacheTime	number	43200000	Cache expiration time in milliseconds (default: 12 hours).
cacheStorage	CacheStorage	localStorage	Storage interface (e.g., localStorage, sessionStorage, indexedDB).
isUpdateCache	boolean	true	Refetch cache every time when true.

AsyncSource.invalidateCacheKey

Invalidates (removes) the cache entry associated with the provided cache key.

This method removes the cached data from the storage based on the provided cacheKey and the cachePrefix. The key used to identify the cached data is a combination of cachePrefix and the provided cacheKey. If the cache item exists in the storage, it will be removed. If an error occurs during the removal, it will be caught and logged, and the method will return null.

Parameters

• cacheKey (string): The key used to identify the cached data to be invalidated. This value is combined with the cachePrefix to form the full cache key.
• storage (CacheStorage, optional): The storage where the cache is stored. If not provided, the default storage (AsyncSource.defaultStorage) will be used.

Returns

• Promise<void | null>: A promise that resolves to void if the cache entry was successfully invalidated, or null if an error occurred during the removal.

Example

// Example usage:
await AsyncSource.invalidateCacheKey("myCacheKey");

// You can also provide a custom storage:
await AsyncSource.invalidateCacheKey("myCacheKey", customStorage);

Example

Sync storage

<template>
    <ul v-loading="isLoading">
        <li v-for="item in items" :key="item.id">
            {{ item.name }}
        </li>
    </ul>
</template>

<script>
import AsyncSource from 'async-source';
import { computed, reactive } from 'vue';

export default {
    name: 'MyComponent',
    setup() {
        function errorHandler(error) {
            console.error(error);
        }

        const source = reactive(
            new AsyncSource(request, errorHandler, {
                requestCacheKey: 'key',
                cacheStorage: sessionStorage,
                isUpdateCache: false,
                debounceTime: 100,
                cacheTime: 24 * 60 * 60 * 1000 // 24h
            })
        );
        source.update();

        const items = computed(() => source.data || []);
        const isLoading = computed(() => source.isLoading);
        
        return {
            items,
            isLoading
        };
    }
}

</script>

Async storage

<template>
    <ul v-loading="isLoading">
        <li v-for="item in items" :key="item.id">
            {{ item.name }}
        </li>
    </ul>
</template>

<script>
import AsyncSource from 'async-source';
import { computed, reactive } from 'vue';
import { get, set, del } from 'idb-keyval';

export default {
    name: 'MyComponent',
    setup() {
        function errorHandler(error) {
            console.error(error);
        }

        const storage = {
            getItem: (key: string) => get(key),
            setItem: (key: string, value: string) => set(key, value),
            removeItem: (key: string) => del(key)
        };

        const source = reactive(
            new AsyncSource(request, errorHandler, {
                requestCacheKey: 'key',
                cacheStorage: storage,
                isUpdateCache: false,
                debounceTime: 100,
                cacheTime: 24 * 60 * 60 * 1000 // 24h
            })
        );
        source.update();

        const items = computed(() => source.data || []);
        const isLoading = computed(() => source.isLoading);
        
        return {
            items,
            isLoading
        };
    }
}

</script>