23 lines
633 B
Markdown
23 lines
633 B
Markdown
---
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title: Case-insensitive substring search
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tags: string
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expertise: beginner
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author: chalarangelo
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cover: blog_images/cup-of-orange.jpg
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firstSeen: 2022-07-28T05:00:00-04:00
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---
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Checks if a string contains a substring, case-insensitive.
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- Use the `RegExp` constructor with the `'i'` flag to create a regular expression, that matches the given `searchString`, ignoring the case.
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- Use `RegExp.prototype.test()` to check if the string contains the substring.
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```js
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const includesCaseInsensitive = (str, searchString) =>
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new RegExp(searchString, 'i').test(str);
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```
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```js
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includesCaseInsensitive('Blue Whale', 'blue'); // true
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```
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