JavaScript String trimEnd() Method

What You’ll Learn

String.prototype.trimEnd() returns a new string with whitespace removed from the end only (same API as MDN String.prototype.trimEnd()). Learn the trimRight alias, how it differs from trim() / trimStart(), five examples, and try-it labs.

Introduction

Sometimes you need to drop trailing spaces or newlines but keep leading indentation. That is exactly what trimEnd() does — clean the right side only.

After trim() was standardized, engines also had a non-standard trimRight(). The standard name is trimEnd() (to match padEnd()), and trimRight remains as an alias of the same function for compatibility.

This page is part of JavaScript String Methods. Related topics include trim() and padEnd().

Understanding the trimEnd() Method

str.trimEnd() builds a new string with trailing whitespace removed. Leading whitespace and middle spaces stay unchanged.

• Returns a new string — the original is unchanged.
• Takes no parameters.
• Only the end (right side) is cleaned.
• trimRight is the same function (alias).

📝 Syntax

General form of String.prototype.trimEnd:

str.trimEnd()
str.trimRight()  // alias — same function

Parameters

None.

Return value

A new string representing str stripped of whitespace from its end. If there is no trailing whitespace, a new string is still returned (essentially a copy).

Exceptions

None for normal string values.

Aliasing

trimRight and trimEnd refer to the exact same function object. In some engines, String.prototype.trimRight.name === "trimEnd".

Common patterns

"   Hello world!   ".trimEnd();  // "   Hello world!"
"   foo  ".trimEnd();            // "   foo"
"\t hi \n".trimEnd();            // "\t hi"
"no-spaces".trimEnd();           // "no-spaces"

Examples Gallery

Examples follow MDN String.trimEnd() patterns. Use View Output or Try It Yourself for each case.

const greeting = "   Hello world!   ";

console.log(greeting);
// Expected output: "   Hello world!   ";

console.log(greeting.trimEnd());
// Expected output: "   Hello world!";

   Hello world!   
   Hello world!

let str = "   foo  ";

console.log(str.length); // 8

str = str.trimEnd();
console.log(str.length); // 6
console.log(str);        // '   foo'

8
6
   foo

const padded = "  hi  ";

console.log(padded.trimEnd() === padded.trimRight());
// true

console.log(String.prototype.trimEnd === String.prototype.trimRight);
// true

console.log(String.prototype.trimRight.name);
// "trimEnd" (in many engines)

true
true
trimEnd

const padded = "  hi  ";

console.log(JSON.stringify(padded.trimEnd()));
// "  hi"

console.log(JSON.stringify(padded.trim()));
// "hi"

console.log(JSON.stringify(padded.trimStart()));
// "hi  "

"  hi"
"hi"
"hi  "

function cleanLine(line) {
  return line.trimEnd();
}

const indented = "    console.log(1);\n";
const cleaned = cleanLine(indented);

console.log(JSON.stringify(cleaned));
// "    console.log(1);"

console.log(cleaned.startsWith("    ")); // true — indent kept
console.log(cleaned.endsWith("\n"));     // false

"    console.log(1);"
true
false

🎯 Common Use Cases

• Preserve indentation — strip trailing spaces/newlines on code lines.
• CSV / fixed-width cleanup — remove end padding, keep start alignment.
• Log / file lines — drop \r / \n at the end only.
• Not for form fields — usually prefer trim() (both ends).
• Not mid-string spaces — use replace / regex for those.

📝 Notes

• Always returns a new string — assign it if you need the result.
• Leading whitespace is intentionally kept.
• trimRight is an alias — prefer trimEnd in new code.
• Does not change spaces in the middle of the string.
• Named to mirror padEnd() after standardization.

💡 Best Practices