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Remove details on pitfalls that are no longer valid (#633)
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filiptammergard authored Aug 3, 2023
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32 changes: 0 additions & 32 deletions README.md
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Expand Up @@ -275,38 +275,6 @@ In most cases it makes very little difference which syntax is used, but you may

</details>

<details>
<summary><b>Minor Pitfalls</b></summary>

These patterns are not supported:

**Conditional rendering**

```tsx
const MyConditionalComponent = ({ shouldRender = false }) =>
shouldRender ? <div /> : false; // don't do this in JS either
const el = <MyConditionalComponent />; // throws an error
```

This is because due to limitations in the compiler, function components cannot return anything other than a JSX expression or `null`, otherwise it complains with a cryptic error message saying that the other type is not assignable to `Element`.

**Array.fill**

```tsx
const MyArrayComponent = () => Array(5).fill(<div />);
const el2 = <MyArrayComponent />; // throws an error
```

Unfortunately just annotating the function type will not help so if you really need to return other exotic types that React supports, you'd need to perform a type assertion:

```tsx
const MyArrayComponent = () => Array(5).fill(<div />) as any as JSX.Element;
```

[See commentary by @ferdaber here](https://github.com/typescript-cheatsheets/react/issues/57).

</details>

<!--END-SECTION:function-components-->

<!--START-SECTION:hooks-->
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32 changes: 0 additions & 32 deletions docs/basic/getting-started/function-components.md
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Expand Up @@ -99,35 +99,3 @@ const VoidFunctionComponent: React.VoidFunctionComponent<Props> = ({
In most cases it makes very little difference which syntax is used, but you may prefer the more explicit nature of `React.FunctionComponent`.

</details>

<details>
<summary><b>Minor Pitfalls</b></summary>

These patterns are not supported:

**Conditional rendering**

```tsx
const MyConditionalComponent = ({ shouldRender = false }) =>
shouldRender ? <div /> : false; // don't do this in JS either
const el = <MyConditionalComponent />; // throws an error
```

This is because due to limitations in the compiler, function components cannot return anything other than a JSX expression or `null`, otherwise it complains with a cryptic error message saying that the other type is not assignable to `Element`.

**Array.fill**

```tsx
const MyArrayComponent = () => Array(5).fill(<div />);
const el2 = <MyArrayComponent />; // throws an error
```

Unfortunately just annotating the function type will not help so if you really need to return other exotic types that React supports, you'd need to perform a type assertion:

```tsx
const MyArrayComponent = () => Array(5).fill(<div />) as any as JSX.Element;
```

[See commentary by @ferdaber here](https://github.com/typescript-cheatsheets/react/issues/57).

</details>

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