How to Convert Case in JavaScript – Full Guide
Published 2026-01-21 · convertcase.in
JavaScript has built-in string methods for case conversion. Here is a complete guide covering toLowerCase, toUpperCase, and custom functions for title case and camelCase.
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1toLowerCase() and toUpperCase()
"HELLO".toLowerCase() // "hello" "hello".toUpperCase() // "HELLO"
2Title Case in JavaScript
No native method. Use: text.replace(/\b\w/g, c => c.toUpperCase())
3camelCase Conversion
text.replace(/\s+(.)/g, (_, c) => c.toUpperCase()).replace(/^./, c => c.toLowerCase())
4snake_case Conversion
text.toLowerCase().replace(/\s+/g, "_")
Frequently Asked Questions
Does JavaScript have a built-in title case method?
No. You need a custom function or a library like Lodash (_.startCase).
Is toLowerCase() locale-aware in JavaScript?
For most Latin languages, yes. For special cases (Turkish dotless i), use toLocaleLowerCase("tr").