trim

Remove whitespace from string ends.

trim

Signature

function trim(str: string, chars?: string): string

Parameters

• str - The string to trim
• chars - Characters to remove (default: whitespace)

Returns

String with leading and trailing whitespace removed.

Examples

import { trim } from 'strio'

// Basic usage
trim("  hello  ")
// "hello"

trim("  hello world  ")
// "hello world"

// Tabs and newlines
trim("\t\nhello\n\t")
// "hello"

// Mixed whitespace
trim("  \t  hello  \n  ")
// "hello"

// No whitespace
trim("hello")
// "hello"

// Only whitespace
trim("   ")
// ""

trim("\t\n")
// ""

// Preserves internal whitespace
trim("  hello   world  ")
// "hello   world"

// Empty string
trim("")
// ""

// Custom characters trim("--hello--", "-") // "hello"

trim("###hello###", "#") // "hello"

trim(" hello ", " ") // "hello"

Use Cases

Clean User Input

import { trim } from 'strio'

function cleanInput(input: string): string {
  return trim(input)
}

cleanInput("  john.doe@example.com  ")
// "john.doe@example.com"

cleanInput("\t  My Name  \n")
// "My Name"

Form Validation

import { trim, isEmpty } from 'strio'

function validateRequired(value: string): boolean {
  return !isEmpty(trim(value))
}

validateRequired("  ")
// false

validateRequired("  John  ")
// true

Normalize Text

import { trim } from 'strio'

function normalizeText(text: string): string {
  return trim(text.toLowerCase())
}

normalizeText("  HELLO WORLD  ")
// "hello world"

Clean Array Values

import { trim } from 'strio'

function trimAll(items: string[]): string[] {
  return items.map(item => trim(item))
}

trimAll(["  apple  ", "  banana  ", "  cherry  "])
// ["apple", "banana", "cherry"]

Parse CSV

import { trim } from 'strio'

function parseCSVLine(line: string): string[] {
  return line.split(',').map(trim)
}

parseCSVLine("John  ,  Doe  ,  john@example.com")
// ["John", "Doe", "john@example.com"]

Clean Multi-line Text

import { trim } from 'strio'

function cleanLines(text: string): string {
  return text
    .split('\n')
    .map(line => trim(line))
    .join('\n')
}

cleanLines("  line 1  \n  line 2  \n  line 3  ")
// "line 1\nline 2\nline 3"

Whitespace Types

Removes all standard whitespace characters:

• Space: (U+0020)
• Tab: \t (U+0009)
• Newline: \n (U+000A)
• Carriage return: \r (U+000D)
• Form feed: \f (U+000C)
• Vertical tab: \v (U+000B)
• Non-breaking space: (U+00A0)
• Other Unicode spaces: Various

import { trim } from 'strio'

// Various whitespace types
trim(" \t\n\r\f\vhello\t\n\r\f\v ")
// "hello"

// Non-breaking space
trim("\u00A0hello\u00A0")
// "hello"

Internal Whitespace

Only removes from ends, preserves internal whitespace:

import { trim } from 'strio'

trim("  hello    world  ")
// "hello    world"
// ✅ Multiple internal spaces preserved

trim("  first\n\nsecond  ")
// "first\n\nsecond"
// ✅ Internal newlines preserved

Performance

• Time Complexity: O(n) in worst case
• Space Complexity: O(n) for result string
• Typically very fast due to native implementation

// Very fast
trim("  hello  ")  // ~0.001ms

// Efficient for large strings
const longText = " ".repeat(1000) + "text" + " ".repeat(1000)
trim(longText)  // ~0.01ms

TypeScript

Full type safety:

import { trim } from 'strio'

const trimmed: string = trim("  hello  ")

// Type error
// trim(123)
// trim(null)

Tips

Trim Specific Characters

For trimming specific characters (not just whitespace):

function trimChar(str: string, char: string): string {
  const escaped = char.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
  const pattern = new RegExp(`^${escaped}+|${escaped}+$`, 'g')
  return str.replace(pattern, '')
}

trimChar("...hello...", ".")
// "hello"

trimChar("///path///", "/")
// "path"

Trim and Collapse Whitespace

import { trim, collapseWhitespace } from 'strio'

function normalize(text: string): string {
  return collapseWhitespace(trim(text))
}

normalize("  hello    world  ")
// "hello world"

Trim Lines and Join

import { trim } from 'strio'

function trimLines(text: string): string {
  return text
    .split('\n')
    .map(line => trim(line))
    .filter(line => line.length > 0)
    .join('\n')
}

trimLines("  line 1  \n\n  line 2  \n  ")
// "line 1\nline 2"

Safe Trim

import { trim } from 'strio'

function safeTrim(value: any): string {
  if (typeof value !== 'string') return ''
  return trim(value)
}

safeTrim("  hello  ")
// "hello"

safeTrim(null)
// ""

safeTrim(123)
// ""

Comparison with Native

trim is essentially the same as native String.prototype.trim():

// Using strio trim
import { trim } from 'strio'
trim("  hello  ")
// "hello"

// Using native trim
"  hello  ".trim()
// "hello"

// strio trim is provided for:
// 1. Consistency with other strio functions
// 2. Easy composition with other utilities
// 3. Null-safe wrapper in some implementations

Related Functions

• collapseWhitespace - Collapse multiple spaces
• stripPrefix / stripSuffix - Remove specific prefix/suffix
• truncate - Shorten strings
• dedent - Remove indentation

Common Patterns

Clean and Validate

import { trim, isEmpty } from 'strio'

function validateEmail(email: string): boolean {
  const cleaned = trim(email)
  return !isEmpty(cleaned) && cleaned.includes('@')
}

Prepare for Comparison

import { trim } from 'strio'

function compareStrings(str1: string, str2: string): boolean {
  return trim(str1).toLowerCase() === trim(str2).toLowerCase()
}

compareStrings("  Hello  ", "hello")
// true

Clean Before Split

import { trim } from 'strio'

function splitClean(text: string, separator: string): string[] {
  return trim(text).split(separator).map(trim)
}

splitClean("  apple,  banana,  cherry  ", ",")
// ["apple", "banana", "cherry"]

See Also

• String Manipulation Guide
• Validation Functions
• Strip Functions