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React custom hook function constantly returns null

ppowell777

Well-Known Coder
I have a multi-use React Hook function, useGetData({url}), that takes a url, does a Fetch API, then returns the resulting JSON array string for further processing in other functions and components. However, useGetData({url}) constantly returns null every time, no matter what I do.

JavaScript:
import { useEffect, useState } from 'react';
import DOMPurify from 'dompurify';

// React function non-component due to naming convention
export const useGetData = ({ url }) => {
    console.log(`url = ${url}`); // Returns the provided URL so all fine here
    const [text, setText] = useState('');
    const [loading, setLoading] = useState(true);

    useEffect(() => {
        const controller = new AbortController();
        const timeout = setTimeout(() => {
            controller.abort();
        }, 5000);
        fetch(url, {
            signal: controller.signal
        })
        .then(response => {
                clearTimeout(timeout);
                if (response.ok && response.status === 200) {
                    return response.text();
                } else if (response.status >= 400) {
                    return Promise.reject(response.statusText);
                }
            })
        .then(async myText => {
            setText(await myText);
            setLoading(false);
        })
        .catch(error => {
                console.error(error);
         });
    });

    if (loading) {
        console.log('empty');
        return '';
    } else {
        console.log('not empty');
        return DOMPurify.sanitize(text);
    }
}

I am using it in this other function (will be used within multiple functions and components in the future), and this constantly returns null which breaks JSON.parse:

JavaScript:
const useGetStateOptions = () => {
    const url = 'http://localhost:8080/react/states.json'
    let stateJsonArrayStr = useGetData({url});
    const [html, setHtml] = useState('');
    const [loading, setLoading] = useState(true);
    
    useEffect(() => {
       let optionHTML = '';
       const stateJsonArray = JSON.parse(stateJsonArrayStr.trim());
       if (typeof stateJsonArray === 'undefined' || stateJsonArray === null || stateJsonArray.length === 0) {
           console.error('state JSON array is undefined');
       } else {
           setLoading(false);
           stateJsonArray.forEach((element) => {
              optionHTML += `<option value="${element.urlEnding}">${element.name}</option>\n`;
           });
          
           setHtml(optionHTML);
       }
    }, [stateJsonArrayStr]);
    
    if (loading) {
        return '';
    } else {
        return DOMPurify.sanitize(html);
    }
};

I am too new to React framework to know how to fix this issue. Can anyone please help?

Thanks
 
<span>import</span> <span>{</span> useEffect<span>,</span> useState <span>}</span> <span>from</span> <span>'react'</span><span>;</span><br><span>import</span> DOMPurify <span>from</span> <span>'dompurify'</span><span>;</span><br><br><span>// React function non-component due to naming convention</span><br><span>export</span> <span>const</span> <span>useGetData</span> <span>=</span> <span>(</span><span><span>{</span> url <span>}</span></span><span>)</span> <span>=&gt;</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span><span></span><span>url = </span><span><span>${</span>url<span>}</span></span><span></span></span><span>)</span><span>;</span> <span>// Returns the provided URL so all fine here</span><br> <span>const</span> <span>[</span>text<span>,</span> setText<span>]</span> <span>=</span> <span>useState</span><span>(</span><span>''</span><span>)</span><span>;</span><br> <span>const</span> <span>[</span>loading<span>,</span> setLoading<span>]</span> <span>=</span> <span>useState</span><span>(</span><span>true</span><span>)</span><span>;</span><br><br> <span>useEffect</span><span>(</span><span>(</span><span>)</span> <span>=&gt;</span> <span>{</span><br> <span>const</span> controller <span>=</span> <span>new</span> <span>AbortController</span><span>(</span><span>)</span><span>;</span><br> <span>const</span> timeout <span>=</span> <span>setTimeout</span><span>(</span><span>(</span><span>)</span> <span>=&gt;</span> <span>{</span><br> controller<span>.</span><span>abort</span><span>(</span><span>)</span><span>;</span><br> <span>}</span><span>,</span> <span>5000</span><span>)</span><span>;</span><br> <span>fetch</span><span>(</span>url<span>,</span> <span>{</span><br> signal<span>:</span> controller<span>.</span>signal<br> <span>}</span><span>)</span><br> <span>.</span><span>then</span><span>(</span><span>response</span> <span>=&gt;</span> <span>{</span><br> <span>clearTimeout</span><span>(</span>timeout<span>)</span><span>;</span><br> <span>if</span> <span>(</span>response<span>.</span>ok <span>&amp;&amp;</span> response<span>.</span>status <span>===</span> <span>200</span><span>)</span> <span>{</span><br> <span>return</span> response<span>.</span><span>text</span><span>(</span><span>)</span><span>;</span><br> <span>}</span> <span>else</span> <span>if</span> <span>(</span>response<span>.</span>status <span>&gt;=</span> <span>400</span><span>)</span> <span>{</span><br> <span>return</span> Promise<span>.</span><span>reject</span><span>(</span>response<span>.</span>statusText<span>)</span><span>;</span><br> <span>}</span><br> <span>}</span><span>)</span><br> <span>.</span><span>then</span><span>(</span><span>async</span> <span>myText</span> <span>=&gt;</span> <span>{</span><br> <span>setText</span><span>(</span><span>await</span> myText<span>)</span><span>;</span><br> <span>setLoading</span><span>(</span><span>false</span><span>)</span><span>;</span><br> <span>}</span><span>)</span><br> <span>.</span><span>catch</span><span>(</span><span>error</span> <span>=&gt;</span> <span>{</span><br> console<span>.</span><span>error</span><span>(</span>error<span>)</span><span>;</span><br> <span>}</span><span>)</span><span>;</span><br> <span>}</span><span>)</span><span>;</span><br><br> <span>if</span> <span>(</span>loading<span>)</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span>'empty'</span><span>)</span><span>;</span><br> <span>return</span> <span>''</span><span>;</span><br> <span>}</span> <span>else</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span>'not empty'</span><span>)</span><span>;</span><br> <span>return</span> DOMPurify<span>.</span><span>sanitize</span><span>(</span>text<span>)</span><span>;</span><br> <span>}</span><br><span>}</span>
 
<span>import</span> <span>{</span> useEffect<span>,</span> useState <span>}</span> <span>from</span> <span>'react'</span><span>;</span><br><span>import</span> DOMPurify <span>from</span> <span>'dompurify'</span><span>;</span><br><br><span>// React function non-component due to naming convention</span><br><span>export</span> <span>const</span> <span>useGetData</span> <span>=</span> <span>(</span><span><span>{</span> url <span>}</span></span><span>)</span> <span>=&gt;</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span><span></span><span>url = </span><span><span>${</span>url<span>}</span></span><span></span></span><span>)</span><span>;</span> <span>// Returns the provided URL so all fine here</span><br> <span>const</span> <span>[</span>text<span>,</span> setText<span>]</span> <span>=</span> <span>useState</span><span>(</span><span>''</span><span>)</span><span>;</span><br> <span>const</span> <span>[</span>loading<span>,</span> setLoading<span>]</span> <span>=</span> <span>useState</span><span>(</span><span>true</span><span>)</span><span>;</span><br><br> <span>useEffect</span><span>(</span><span>(</span><span>)</span> <span>=&gt;</span> <span>{</span><br> <span>const</span> controller <span>=</span> <span>new</span> <span>AbortController</span><span>(</span><span>)</span><span>;</span><br> <span>const</span> timeout <span>=</span> <span>setTimeout</span><span>(</span><span>(</span><span>)</span> <span>=&gt;</span> <span>{</span><br> controller<span>.</span><span>abort</span><span>(</span><span>)</span><span>;</span><br> <span>}</span><span>,</span> <span>5000</span><span>)</span><span>;</span><br> <span>fetch</span><span>(</span>url<span>,</span> <span>{</span><br> signal<span>:</span> controller<span>.</span>signal<br> <span>}</span><span>)</span><br> <span>.</span><span>then</span><span>(</span><span>response</span> <span>=&gt;</span> <span>{</span><br> <span>clearTimeout</span><span>(</span>timeout<span>)</span><span>;</span><br> <span>if</span> <span>(</span>response<span>.</span>ok <span>&amp;&amp;</span> response<span>.</span>status <span>===</span> <span>200</span><span>)</span> <span>{</span><br> <span>return</span> response<span>.</span><span>text</span><span>(</span><span>)</span><span>;</span><br> <span>}</span> <span>else</span> <span>if</span> <span>(</span>response<span>.</span>status <span>&gt;=</span> <span>400</span><span>)</span> <span>{</span><br> <span>return</span> Promise<span>.</span><span>reject</span><span>(</span>response<span>.</span>statusText<span>)</span><span>;</span><br> <span>}</span><br> <span>}</span><span>)</span><br> <span>.</span><span>then</span><span>(</span><span>async</span> <span>myText</span> <span>=&gt;</span> <span>{</span><br> <span>setText</span><span>(</span><span>await</span> myText<span>)</span><span>;</span><br> <span>setLoading</span><span>(</span><span>false</span><span>)</span><span>;</span><br> <span>}</span><span>)</span><br> <span>.</span><span>catch</span><span>(</span><span>error</span> <span>=&gt;</span> <span>{</span><br> console<span>.</span><span>error</span><span>(</span>error<span>)</span><span>;</span><br> <span>}</span><span>)</span><span>;</span><br> <span>}</span><span>)</span><span>;</span><br><br> <span>if</span> <span>(</span>loading<span>)</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span>'empty'</span><span>)</span><span>;</span><br> <span>return</span> <span>''</span><span>;</span><br> <span>}</span> <span>else</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span>'not empty'</span><span>)</span><span>;</span><br> <span>return</span> DOMPurify<span>.</span><span>sanitize</span><span>(</span>text<span>)</span><span>;</span><br> <span>}</span><br><span>}</span>
 
<span>import</span> <span>{</span> useEffect<span>,</span> useState <span>}</span> <span>from</span> <span>'react'</span><span>;</span><br><span>import</span> DOMPurify <span>from</span> <span>'dompurify'</span><span>;</span><br><br><span>// React function non-component due to naming convention</span><br><span>export</span> <span>const</span> <span>useGetData</span> <span>=</span> <span>(</span><span><span>{</span> url <span>}</span></span><span>)</span> <span>=&gt;</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span><span></span><span>url = </span><span><span>${</span>url<span>}</span></span><span></span></span><span>)</span><span>;</span> <span>// Returns the provided URL so all fine here</span><br> <span>const</span> <span>[</span>text<span>,</span> setText<span>]</span> <span>=</span> <span>useState</span><span>(</span><span>''</span><span>)</span><span>;</span><br> <span>const</span> <span>[</span>loading<span>,</span> setLoading<span>]</span> <span>=</span> <span>useState</span><span>(</span><span>true</span><span>)</span><span>;</span><br><br> <span>useEffect</span><span>(</span><span>(</span><span>)</span> <span>=&gt;</span> <span>{</span><br> <span>const</span> controller <span>=</span> <span>new</span> <span>AbortController</span><span>(</span><span>)</span><span>;</span><br> <span>const</span> timeout <span>=</span> <span>setTimeout</span><span>(</span><span>(</span><span>)</span> <span>=&gt;</span> <span>{</span><br> controller<span>.</span><span>abort</span><span>(</span><span>)</span><span>;</span><br> <span>}</span><span>,</span> <span>5000</span><span>)</span><span>;</span><br> <span>fetch</span><span>(</span>url<span>,</span> <span>{</span><br> signal<span>:</span> controller<span>.</span>signal<br> <span>}</span><span>)</span><br> <span>.</span><span>then</span><span>(</span><span>response</span> <span>=&gt;</span> <span>{</span><br> <span>clearTimeout</span><span>(</span>timeout<span>)</span><span>;</span><br> <span>if</span> <span>(</span>response<span>.</span>ok <span>&amp;&amp;</span> response<span>.</span>status <span>===</span> <span>200</span><span>)</span> <span>{</span><br> <span>return</span> response<span>.</span><span>text</span><span>(</span><span>)</span><span>;</span><br> <span>}</span> <span>else</span> <span>if</span> <span>(</span>response<span>.</span>status <span>&gt;=</span> <span>400</span><span>)</span> <span>{</span><br> <span>return</span> Promise<span>.</span><span>reject</span><span>(</span>response<span>.</span>statusText<span>)</span><span>;</span><br> <span>}</span><br> <span>}</span><span>)</span><br> <span>.</span><span>then</span><span>(</span><span>async</span> <span>myText</span> <span>=&gt;</span> <span>{</span><br> <span>setText</span><span>(</span><span>await</span> myText<span>)</span><span>;</span><br> <span>setLoading</span><span>(</span><span>false</span><span>)</span><span>;</span><br> <span>}</span><span>)</span><br> <span>.</span><span>catch</span><span>(</span><span>error</span> <span>=&gt;</span> <span>{</span><br> console<span>.</span><span>error</span><span>(</span>error<span>)</span><span>;</span><br> <span>}</span><span>)</span><span>;</span><br> <span>}</span><span>)</span><span>;</span><br><br> <span>if</span> <span>(</span>loading<span>)</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span>'empty'</span><span>)</span><span>;</span><br> <span>return</span> <span>''</span><span>;</span><br> <span>}</span> <span>else</span> <span>{</span><br> console<span>.</span><span>log</span><span>(</span><span>'not empty'</span><span>)</span><span>;</span><br> <span>return</span> DOMPurify<span>.</span><span>sanitize</span><span>(</span>text<span>)</span><span>;</span><br> <span>}</span><br><span>}</span>
 

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