Welcome to Software Development on Codidact!

Will you help us build our independent community of developers helping developers? We're small and trying to grow. We welcome questions about all aspects of software development, from design to code to QA and more. Got questions? Got answers? Got code you'd like someone to review? Please join us.

Post History

75%

+4 −0

Q&A Are there other reasons why useEffect might not be defined apart from not importing it?

I am creating a button that once clicked will change from off to on with react and i am also creating a responsive clock through useEffect. Yet the code still return that useEffect is undefined th...

2 answers · posted 11mo ago by Brian‭ · last activity 11mo ago by jmathew‭

Question reactjs react-hooks

#4: Post edited by

Alexei‭ · 2023-05-25T06:08:48Z (11 months ago)
added related tag

Copy Link

Raw

Markdown

reactjs

reactjs react-hooks

#3: Post edited by

trichoplax‭ · 2023-05-25T05:05:27Z (11 months ago)
Fix backticks so syntax highlighting will work, fix typo in title

Copy Link

Raw

Markdown

~~Are there other reasons why useEfffect might not be defined apart from not importing it?~~

Are there other reasons why useEffect might not be defined apart from not importing it?

I am creating a button that once clicked will change from off to on with react and i am also creating a responsive clock through useEffect.
Yet the code still return that useEffect is undefined though i imported useState.
~~``````import {useState} from 'react';~~
import "./styles.css";
export default function App() {
let [PresentState, setPresentState] = useState(false);
let [time, seTime] = useState("00:00:00");
function toggleState() {
setPresentState((prevState) => !prevState);
}
function getTime() {
return new Date().getTime();
}
useEffect(() => {
setTime(getTime());
console.log();
return () => {};
},[]);
return (
<div className="app">
<button onClick={toggleState} className="btn">
{PresentState ? "On" : "Off"}
</button>
<time>00:00:00</time>
</div>
);
}
``````

I am creating a button that once clicked will change from off to on with react and i am also creating a responsive clock through useEffect.
Yet the code still return that useEffect is undefined though i imported useState.
```
import {useState} from 'react';
import "./styles.css";
export default function App() {
let [PresentState, setPresentState] = useState(false);
let [time, seTime] = useState("00:00:00");
function toggleState() {
setPresentState((prevState) => !prevState);
}
function getTime() {
return new Date().getTime();
}
useEffect(() => {
setTime(getTime());
console.log();
return () => {};
},[]);
return (
<div className="app">
<button onClick={toggleState} className="btn">
{PresentState ? "On" : "Off"}
</button>
<time>00:00:00</time>
</div>
);
}
```

#2: Post edited by

Brian‭ · 2023-05-24T06:23:52Z (11 months ago)

Copy Link

Raw

Markdown

I am creating a button that once clicked will change from off to on with react and i am also creating a responsive clock through useEffect.
Yet the code still return that useEffect is undefined though i imported useState.
~~`import {useState} from 'react';~~
import "./styles.css";
export default function App() {
let [PresentState, setPresentState] = useState(false);
let [time, seTime] = useState("00:00:00");
function toggleState() {
setPresentState((prevState) => !prevState);
}
function getTime() {
return new Date().getTime();
}
useEffect(() => {
setTime(getTime());
console.log();
return () => {};
},[]);
return (
<div className="app">
<button onClick={toggleState} className="btn">
{PresentState ? "On" : "Off"}
</button>
<time>00:00:00</time>
</div>
);
}
`

I am creating a button that once clicked will change from off to on with react and i am also creating a responsive clock through useEffect.
Yet the code still return that useEffect is undefined though i imported useState.
``````import {useState} from 'react';
import "./styles.css";
export default function App() {
let [PresentState, setPresentState] = useState(false);
let [time, seTime] = useState("00:00:00");
function toggleState() {
setPresentState((prevState) => !prevState);
}
function getTime() {
return new Date().getTime();
}
useEffect(() => {
setTime(getTime());
console.log();
return () => {};
},[]);
return (
<div className="app">
<button onClick={toggleState} className="btn">
{PresentState ? "On" : "Off"}
</button>
<time>00:00:00</time>
</div>
);
}
``````

#1: Initial revision by

Brian‭ · 2023-05-24T06:22:50Z (11 months ago)

Copy Link

Raw

Markdown

Are there other reasons why useEfffect might not be defined apart from not importing it?

I am creating a button that once clicked will change from off to on with react and i am also creating a responsive clock through useEffect.

Yet the code still return that useEffect is undefined though i imported useState.

`import {useState} from 'react';
import "./styles.css";
export default function App() {
  let [PresentState, setPresentState] = useState(false);
  let [time, seTime] = useState("00:00:00");
  function toggleState() {
    setPresentState((prevState) => !prevState);
  }
  function getTime() {
    return new Date().getTime();
  }

  useEffect(() => {
    setTime(getTime());
    console.log();
    return () => {};
  },[]);
  return (
    <div className="app">
      <button onClick={toggleState} className="btn">
        {PresentState ? "On" : "Off"}
      </button>
      <time>00:00:00</time>
    </div>
  );
}

`

reactjs

Communities

Post History