Naming Style Converter

Naming-style conversion: the five styles and the traps in between

The five styles

The tool's process is: first split the input into words, then rejoin them in the target style. So the key to understanding conversion behavior is the word-splitting rule, not the joining.

The word-splitting rule and its boundaries

To split correctly you must first find the word boundaries. The tool uses three rules:

The second rule exists specifically for abbreviations. Without it, HTTPResponse would split into h / t / t / p / response, which is plainly wrong. A naive implementation that "breaks before every uppercase letter" ruins every name containing an abbreviation — the most common conversion bug.

Yet even with this rule, some cases are unsolvable:

• userID splits into user / id (correct), but userIDs may split into user / i / ds (because IDs is "uppercase + uppercase + lowercase"). An abbreviation plus a plural cannot be solved perfectly by rules.
• A single all-upper word cannot tell abbreviation from ordinary word. ID and URL become id and url in camelCase (by convention), but whether OK to ok or IO to io is appropriate is debatable.
• A lowercase string with no separators cannot be split. userlogin is treated as a single word; the tool will not (and should not) guess a boundary in the middle.

So conversion is not bidirectionally reversible: userID to USER_ID to userId differs from the original after the round trip. To preserve fidelity, confirm the original style before converting and check the result.

Practical traps during conversion

• An abbreviation's case cannot be recovered from other styles. Both http_response and HTTP_response become HttpResponse in PascalCase, losing the fact that "HTTP is an abbreviation". You need HTTPResponse only by hand.
• The position of digits. For utf8Encode or base64Encode, how the digit-letter boundary affects splitting differs between tools and may yield either utf_8_encode or utf8_encode. Check after converting.
• kebab-case cannot be an identifier. In some languages it is a minus expression, and in JSON keys it needs quotes. It suits URLs and CSS, not variable names.
• Database columns and code fields often use different styles. A common need is converting user_login_count (database) to userLoginCount (a field in code). In batch, do not convert something already camelCase again (idempotent, harmless), but when converting kebab to snake the hyphen is swallowed, so confirm no extra separator remains.
• Case-sensitive languages. In Go an initial uppercase means exported (public) and lowercase means private. Converting to PascalCase changes visibility, which may be what you want or may be a compile error.

How to use the tool

Enter an identifier in any style and the tool gives all five styles at once; copy the line you need. Spaces, hyphens, underscores, and dots in the input are all recognized as word boundaries.

It suits deciding the target style when renaming a variable, converting a backend's snake_case field to the frontend's camelCase, and generating a JS identifier from a CSS class name. Conversion runs locally in your browser.