Lodash _.toUpper() Method

What You’ll Learn

By the end of this tutorial, you’ll use Lodash’s _.toUpper() confidently in real string workflows.

What Is _.toUpper()?

_.toUpper() converts every character in the input string to uppercase. It mirrors _.toLower() and is handy when you want shouting-case labels, coupon codes, or consistent display formatting inside a Lodash-heavy codebase.

📝 Syntax

_.toUpper([string=''])

Syntax Rules

• string — Optional. Defaults to '' when omitted.
• Return value — A new string with all uppercase-mappable characters converted.
• Immutable — Original string is never modified.
• Coercion — Non-strings are converted with String() first.

import toUpper from "lodash/toUpper";

const label = "hello, world!";
const result = toUpper(label);
// -> "HELLO, WORLD!"

Examples Gallery

Practical _.toUpper() patterns with copy-ready code and interactive Try It Yourself labs.

const text = "hello, world!";
const upper = _.toUpper(text);

console.log(upper);
// -> "HELLO, WORLD!"

console.log(text);
// still "hello, world!"

upper: HELLO, WORLD!
text: hello, world!

function formatLabel(input) {
  if (typeof input !== "string") return "";
  return _.toUpper(_.trim(input));
}

console.log(formatLabel("  draft  "));
// -> "DRAFT"

DRAFT

const messy = "   active   ";
const banner = _.toUpper(_.trim(messy));

console.log(banner);
// -> "ACTIVE"

banner: ACTIVE

const entered = "save20";
const code = _.toUpper(entered);
// -> "SAVE20"

code: SAVE20

const sections = ["intro", "setup", "deploy"];
const labels = sections.map(_.toUpper);
// -> ["INTRO", "SETUP", "DEPLOY"]

["INTRO", "SETUP", "DEPLOY"]

const text = "hello";
const native = text.toUpperCase();
const lodash = _.toUpper(text);
// both -> "HELLO"

Both approaches yield: HELLO

📝 Notes

• _.toUpper() is non-mutating.
• Omitting the argument returns "".
• Non-string values are coerced before conversion.
• Some Unicode characters have no uppercase form and stay unchanged.
• Chain with _.trim() to remove surrounding whitespace first.
• Opposite helper: _.toLower().

💡 Best Practices