21 lines
667 B
Markdown
21 lines
667 B
Markdown
---
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title: capitalize
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tags: string,intermediate
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---
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Capitalizes the first letter of a string.
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- Use array destructuring and `String.prototype.toUpperCase()` to capitalize the first letter of the string.
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- Use `Array.prototype.join('')` to combine the capitalized `first` with the `...rest` of the characters.
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- Omit the `lowerRest` parameter to keep the rest of the string intact, or set it to `true` to convert to lowercase.
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```js
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const capitalize = ([first, ...rest], lowerRest = false) =>
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first.toUpperCase() + (lowerRest ? rest.join('').toLowerCase() : rest.join(''));
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```
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```js
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capitalize('fooBar'); // 'FooBar'
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capitalize('fooBar', true); // 'Foobar'
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```
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