Example 1 — Official: Fred
Lowercase a capitalized name’s first letter.
Lodash
_.lowerFirst('Fred');
// → 'fred'How It Works
- First.
Fbecomesf. - Rest.
redstays as-is. - Result.
fred. - Official. Same as the Lodash docs.
Lodash _.lowerFirst() Method
Definition
Converts the first character of a string to lowercase and leaves the rest unchanged. Inverse of _.upperFirst. Part of Lodash String (stable — not deprecated).
Pass the string and options shown below. Check the return type before you chain another helper.
Syntax
Call _.lowerFirst. Start with this line.
Lodash
_.lowerFirst([string=''])| Call | What it does |
|---|---|
_.lowerFirst([string='']) | Primary signature. |
_.lowerFirst(string) | Transform or inspect a string. |
Prefer import lowerFirst from "lodash/lowerFirst" when you want a smaller bundle.
Library declarations
Lodash
_.lowerFirst([string=''])Parameters
| Parameter | Description |
|---|---|
| string | Optional. Input to convert |
Return Value
| Return Value | Description |
|---|---|
| * | New string (first char lower) |
Lodash Examples
Example 1 — Official:
Example 2 — Official: FRED
Only the first character changes — the rest stay uppercase.
Lodash
_.lowerFirst('FRED');
// → 'fRED'How It Works
- Not toLower. Does not make the whole string lower.
- F → f. First char only.
- RED. Unchanged.
- Official. Docs highlight this contrast.
Example 3 — PascalCase → camelCase
Turn a type/class style name into a JS identifier.
Lodash
_.lowerFirst('UserName');
// → 'userName'
_.lowerFirst('XMLParser');
// → 'xMLParser'How It Works
- UserName. Typical Pascal → camel result.
- XMLParser. Only
Xchanges — acronyms need care. - No split. Middle capitals stay.
- Tip. For smarter word casing, use
_.camelCase.
Example 4 — Already lowercase / empty
Safe no-ops for common edge inputs.
Lodash
_.lowerFirst('fred');
// → 'fred'
_.lowerFirst('');
// → ''How It Works
- Already lower. First char stays
f. - Empty. Returns
''. - Safe. Fine to call unconditionally.
- Default. Missing arg →
''.
Example 5 — vs upperFirst / toLower / lowerCase
Same input, different helpers.
Lodash
var s = 'FRED';
_.lowerFirst(s); // → 'fRED'
_.upperFirst(s); // → 'FRED'
_.toLower(s); // → 'fred'
_.lowerCase(s); // → 'fred'How It Works
- lowerFirst. First char only.
- upperFirst. Opposite for the first char.
- toLower. Entire string lower.
- lowerCase. Word-aware lower (spaces for multi-word input).
Compatibility
Browser & Runtime Support
_.lowerFirst is a Lodash 4.x String helper. It runs anywhere Lodash runs — modern browsers (CDN or bundle) and Node.js / Bun / Deno with npm install lodash or lodash/lowerFirst. Native idea: s.charAt(0).toLowerCase() + s.slice(1).
Stable · Lodash 4.x
_.lowerFirst()
Available in [email protected] and lodash/lowerFirst modular import. Works in evergreen browsers and current Node LTS when Lodash is installed.
100% With Lodash 4.x
Google Chrome Supported · Desktop & Mobile
Full supportMozilla Firefox Supported · Desktop & Mobile
Full supportApple Safari Supported · macOS & iOS
Full supportMicrosoft Edge Supported · Chromium
Full supportInternet Explorer No native support · Use a polyfill
PolyfillOpera Supported · Modern versions
Full supportSamsung Internet Supported · Android
Full supportBun Supported · JavaScript runtime
SupportedDeno Supported · JavaScript runtime
SupportedNode.js Supported · Server runtime
SupportedAndroid WebView Supported · Modern WebView
Full support_.lowerFirst Lodash 4.x
Bottom line: Safe for production. Use for Pascal→camel tweaks; use toLower/camelCase for broader transforms.
Frequently Asked Questions
_.lowerFirst([string='']) lowercases only the first character. Official: _.lowerFirst('Fred') → 'fred'; _.lowerFirst('FRED') → 'fRED'.
_.toLower lowercases the whole string. _.lowerFirst changes only the first character.
_.lowerCase lowercases and inserts spaces between words. _.lowerFirst does not split or reformat words.
Commonly to turn PascalCase into camelCase identifiers (UserName → userName) without touching the rest.
The string is effectively unchanged.
_.upperFirst() uppercases only the first character.
Next: _.pad()
Pad a string on both sides to reach a target length.
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