collapseWhitespace — GTM Variable Template for String

VARIABLES › STRING

collapseWhitespace EXTENDED String

Direct (.tpl) Apply (.tpl) Add to GTM

Sanitizes a string by replacing line breaks and tabs with spaces, collapsing multiple whitespace characters into a single space, and trimming leading/trailing whitespace.

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Examples

Collapse multiple spaces▶ Try

INPUT

Text To Sanitize: Hello world test

OUTPUT

Hello world test

Replace line breaks and tabs▶ Try

INPUT

Text To Sanitize: Line1\nLine2\tTabbed\rReturn

OUTPUT

Line1 Line2 Tabbed Return

Non-string input returns undefined▶ Try

INPUT

Text To Sanitize: 12345

OUTPUT

undefined

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Live Sandbox

This is what you'll see when you open this variable in Google Tag Manager. Hover the icons for details.

collapseWhitespace

Read-Only Try Live

Text To Sanitize

💾 The string to sanitize and clean.

Supported formats:
  ✓ String

Input Setup

Input Function (optional)

⚙️ Optional pre-processing function applied to the input before internal logic (e.g., normalize encoding, convert to string). Internal transformations such as whitespace normalization will still apply afterward.

Result Handling

Output Function (optional)

⚙️ Optional function to apply to the result before returning it (e.g., str => str.toUpperCase(), val => val + ' cleaned' for string modifications). Useful for chaining transformations on the output.

Text To Sanitize string

💡 Type any text to see the result update live

🎯 Using special value — click input to type instead

Test with:

Falsy undefined null "" empty 0 false NaN

Truthy true 42 "hello" {} empty [] empty {a:1} [1,2,3]

🔗 Result Handling — Chain Variables

Chain apply-mode variables to the output. Each variable receives the result of the previous one.

collapseWhitespace()

+ Chain another variable

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Related Variables

Same category: String

→ charAt → concat → countWordsInString → endsWith → extract → extractFirstSegment → extractNumber → fromBase64 → indexOf → left → matchAll → matchRegex → normalizeEmail → normalizePhone → padEnd → padStart → parseJSON → replaceAll → replaceAllWithRegex → replaceFirst → right → safeSplit → search → slice → slugify → split → startsWith → stripAccents → stripHtml → substringAfter → substringBefore → test → toBase64 → toCamelCase → toJsonString → toKebabCase → toLocaleLowerCase → toLocaleUpperCase → toLowerCase → toNumber → toSnakeCase → toStartCase → toString → toStringRepresentation → toUpperCase → toUpperFirst → trim → trimEnd → trimStart → truncate

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Under the Hood

📜 View Implementation Code

/**
* Sanitizes a string by:
* - Replacing line breaks and tabs with spaces
* - Collapsing multiple whitespace characters into a single space
* - Trimming leading and trailing whitespace
*
* @param {string} data.src - The string to sanitize.
* @param {Function|string} [data.out] - Optional output handler: function to transform result or string with format.
*
* Direct-mode specific parameters:
* @param {Function} [data.pre] - Optional pre-processor function to transform src before sanitizing.
*
* @returns {string|undefined} The sanitized string or undefined if input is not a string.
*
* @framework ggLowCodeGTMKit
*/
const collapseWhitespace = function(input) {
   if (typeof input !== 'string') {
       return undefined;
   }
   let cleaned = input.split('\n').join(' ')
                      .split('\r').join(' ')
                      .split('\t').join(' ');
   while (cleaned.indexOf('  ') !== -1) {
       cleaned = cleaned.split('  ').join(' ');
   }
   return cleaned.trim();
};

const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);

// ===============================================================================
// collapseWhitespace - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const value = applyCast(data.pre, data.src);
return out(collapseWhitespace(value));
// ===============================================================================
// collapseWhitespace() – Apply Mode
// ===============================================================================
/*
return function(value) {
  return out(collapseWhitespace(value));
};
*/

🧪 View Test Scenarios (5 tests)

✅ '[example] Collapse multiple spaces'
✅ '[example] Replace line breaks and tabs'
✅ String with leading and trailing whitespace - trims edges
✅ String with mixed whitespace issues - sanitizes completely
✅ '[example] Non-string input returns undefined'