By the end of this tutorial, you’ll confidently use Lodash’s _.lowerCase() method in real JavaScript projects.
Call _.lowerCase(string) for spaced lowercase.
camelCase splits into separate words.
Compare queries case-insensitively.
Native case vs Lodash word rules.
Whole string vs first char only.
Normalize once before indexing.
_.lowerCase()?It converts a string to lowercase and separates words with spaces, following Lodash word-boundary rules.
Import only what you need: import lowerCase from "lodash/lowerCase" keeps bundles small.
_.lowerCase([string=''])import lowerCase from "lodash/lowerCase";
const original = "Hello World!";
const result = lowerCase(original);
console.log(result);
// -> "hello world"| Task | Code pattern | Result |
|---|---|---|
| Basic phrase | _.lowerCase('Hello World!') | hello world |
| From camelCase | _.lowerCase('fooBar') | foo bar |
| Search normalize | _.lowerCase(query) | Comparable text |
| Filter array | items.filter(i => _.lowerCase(i).includes(q)) | Case-insensitive |
| Native compare | str.toLowerCase() | Case only, no spaces |
| First char only | _.lowerFirst(str) | helloWorld style |
NoReturns new string
Words spacedNot compact
All lowerFull string
_.upperCase()Uppercase variant
Every argument to _.lowerCase() and what it controls:
stringOptionalThe string to convert. When omitted or empty, returns an empty string.
_.lowerCase('Hello World')return valueNew stringLowercase words separated by spaces. The original string is unchanged.
// -> 'hello world'separatorsImplicitSpaces, hyphens, underscores, punctuation, and case changes define word boundaries before lowercasing.
_.lowerCase('foo_bar-baz')edge casesImportantPunctuation is stripped, not preserved. Non-strings are coerced; numbers become string digits.
_.lowerCase('Élève')For compact lowercase without word spacing, use native String.prototype.toLowerCase(). For hyphens instead of spaces, use _.kebabCase().
Practical _.lowerCase() patterns with copy-ready code and interactive Try It Yourself labs.
Convert phrases and camelCase identifiers to lowercase words.
Turn a greeting with punctuation into lowercase words separated by spaces.
const original = "Hello World!";
const result = _.lowerCase(original);
console.log(result);
// -> "hello world"Punctuation is removed and words are lowercased with spaces between them.
Normalize data and power case-insensitive search.
Split a JavaScript identifier into readable lowercase words.
const input = "fooBarBaz";
const result = _.lowerCase(input);
console.log(result);
// -> "foo bar baz"Capital letters signal word boundaries before lowercasing.
Filter an array using a normalized query and normalized items.
const items = ["Apple Pie", "Banana", "Apricot Tart"];
const query = "APRICOT";
const q = _.lowerCase(query);
const matches = items.filter((item) =>
_.lowerCase(item).includes(q)
);
console.log(matches);
// -> ["Apricot Tart"]Both query and items are normalized so case differences do not block matches.
Lowercase strings containing accented Latin letters.
const input = "HÉLLÖ WÖRLD";
const result = _.lowerCase(input);
console.log(result);
// -> "héllö wörld"Unicode letters are lowercased while word spacing rules still apply.
Edge cases and comparisons with native methods.
Numbers and empty strings are handled safely.
console.log(_.lowerCase(""));
console.log(_.lowerCase(123));
// -> ""
// -> "123"Lodash coerces non-strings before applying case rules.
See how native lowercasing differs from Lodash word spacing.
import lowerCase from "lodash/lowerCase";
const input = "fooBar";
console.log(input.toLowerCase()); // -> "foobar"
console.log(lowerCase(input)); // -> "foo bar"
// lowerFirst only changes the first character:
console.log(_.lowerFirst("FooBar")); // -> "fooBar"Use toLowerCase() when you only need case change; use _.lowerCase() when you need word separation too.
_.lowerCase() WorksLodash coerces null/undefined to an empty string.
Spaces, punctuation, and case changes define words.
Each word is converted to lowercase.
Words are joined with single spaces.
_.lowerCase() adds spaces—not the same as toLowerCase()._.lowerCase() is the go-to Lodash helper when you need lowercase text with readable word spacing—ideal for search normalization, display labels from camelCase keys, and data cleanup.
When you only need to change letter case, use toLowerCase(). For URL slugs or CSS tokens, reach for _.kebabCase() instead.
_.lowerCase()Words with spaces.
BasicscamelCase splits.
RulesNormalize both sides.
PatternCase only.
CompareFirst char only.
Related_.lowerCase() is the lowercase counterpart of _.upperCase()—both add spaces at word boundaries. For URL slugs use _.kebabCase(); for only the first character, use _.lowerFirst().
Open the Try It editor and run the examples with your own input.
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