Fix JavaScript Async Await Promise Pending Data Utilities

When your JavaScript async await function returns promise pending instead of data, these utility functions provide ready-to-use solutions. Copy and use these code snippets to handle async operations correctly.

Basic Async/Await Wrapper #

This utility ensures proper awaiting of async functions:

Promise Pending Detector #

Utility to detect and handle promise pending states:

// Detect if a value is a pending promise
function isPromisePending(value) {
    return value instanceof Promise && 
           value.constructor === Promise &&
           typeof value.then === 'function';
}

// Utility to resolve any value (promise or not)
async function resolveValue(value) {
    if (isPromisePending(value)) {
        return await value;
    }
    return value;
}

// Usage
async function handleUnknownValue(unknownValue) {
    const resolved = await resolveValue(unknownValue);
    console.log('Resolved value:', resolved);
    return resolved;
}

Async Function Validator #

Ensures functions are properly awaited before use:

Promise State Checker #

Monitor and debug promise states in real-time:

// Enhanced promise state checker
function createPromiseStateChecker(promise, label = 'Promise') {
    const states = {
        pending: 'pending',
        fulfilled: 'fulfilled',
        rejected: 'rejected'
    };
    
    let currentState = states.pending;
    
    promise
        .then(value => {
            currentState = states.fulfilled;
            console.log(`${label} fulfilled with:`, value);
            return value;
        })
        .catch(error => {
            currentState = states.rejected;
            console.log(`${label} rejected with:`, error.message);
            throw error;
        });
    
    return {
        getState: () => currentState,
        isPending: () => currentState === states.pending,
        isFulfilled: () => currentState === states.fulfilled,
        isRejected: () => currentState === states.rejected
    };
}

// Usage example
function testPromiseStateChecker() {
    const slowPromise = new Promise(resolve => 
        setTimeout(() => resolve('Slow result'), 2000)
    );
    
    const checker = createPromiseStateChecker(slowPromise, 'SlowAPI');
    
    console.log('Initial state:', checker.getState()); // pending
    
    setTimeout(() => {
        console.log('After 1s state:', checker.getState()); // still pending
    }, 1000);
    
    return slowPromise;
}

Async Retry Utility #

Handles promise pending issues with automatic retries:

Promise Timeout Handler #

Prevents promises from hanging indefinitely:

// Add timeout to prevent promises from staying pending forever
function withTimeout(promise, timeoutMs = 5000) {
    return Promise.race([
        promise,
        new Promise((_, reject) => 
            setTimeout(() => reject(new Error(`Operation timed out after ${timeoutMs}ms`)), timeoutMs)
        )
    ]);
}

// Usage with async/await
async function fetchWithTimeout(url, timeout = 3000) {
    try {
        const response = await withTimeout(fetch(url), timeout);
        return await response.json();
    } catch (error) {
        if (error.message.includes('timed out')) {
            console.error('Request timed out - check your connection');
        }
        throw error;
    }
}

Sequential Async Processor #

Process multiple async operations while avoiding promise pending issues:

Usage Tips #

1. Copy the utilities you need - Don't include all utilities if you only need one
2. Customize timeouts - Adjust timeout values based on your API response times
3. Add logging - Include console.log statements for debugging during development
4. Handle errors gracefully - Always include error handling in your implementations
5. Test with real data - Verify utilities work with your actual API calls

These utilities solve the common problem of why JavaScript async await functions return promise pending instead of data by ensuring proper awaiting and error handling.

For more complex async scenarios, see our async error handling guide and async basics tutorial.