test — GTM Variable Template for String

VARIABLES › STRING

test CORE String

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

Tests whether a regular expression pattern matches a string. Returns true if a match is found, false otherwise. Useful for validation and conditional logic.

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When to Use This

String Manipulation

Transform, clean, and normalize text data for consistent downstream processing.

Extraction

Pull specific values, segments, or patterns from complex data structures.

Comparison

Test equality, containment, and ordering between values.

Regex

Pattern matching, extraction, and replacement using regular expressions.

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Examples

Pattern matches▶ Try

INPUT

String to Search: Hello World
Regular Expression Pattern: World

OUTPUT

true

No match returns false▶ Try

INPUT

String to Search: Hello World
Regular Expression Pattern: xyz

OUTPUT

false

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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.

test

Read-Only Try Live

String to Search

💾 The string to search within.

Supported formats:
  ✓ String

Regular Expression Pattern

🔍 The regular expression pattern to search for. Returns the index of the first match.

Supported formats:
  ✓ String (regex pattern): "d+", "[a-z]+", "test"

⚠️ Escaping note: In this UI field, use single backslash (e.g., d+ for digits). GTM automatically handles the escaping.

Input Setup

Input Function (optional)

⚙️ Optional pre-processing function applied to the string before searching (e.g., normalize case with str => str.toLowerCase(), trim whitespace).

Result Handling

Output Function (optional)

⚙️ Optional function to apply to the result index before returning it (e.g., idx => idx !== -1 for boolean check, idx => idx + 1 for 1-based indexing). Useful for chaining transformations on the output.

String to Search 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]

Regular Expression Pattern string

🔗 Result Handling — Chain Variables

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

test()

+ Chain another variable

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Related Variables

Same category: String

→ charAt → collapseWhitespace → 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 → 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

/**
 * Tests whether a given regular expression pattern matches the string.
 *
 * @param {string} data.str - The string to search within.
 * @param {string} data.pat - The regular expression pattern to match in the string.
 * @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 str before matching.
 *
 * @returns {boolean} Returns true if a match is found, false if no match is found.
 *
 * @framework ggLowCodeGTMKit
 */
const test = function(stringToMatch, regexPattern) {
    if (typeof stringToMatch !== 'string' || typeof regexPattern !== 'string') {
        return false;
    }
    return stringToMatch.search(regexPattern) !== -1;
};
const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);
// ===============================================================================
// test - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const processedString = applyCast(data.pre, data.str);
return out(test(processedString, data.pat));
// ===============================================================================
// test(...) – Apply Mode
// ===============================================================================
/*
return function(stringToMatch, regexPattern) {
   return out(test(stringToMatch, data.pat));
};
*/

🧪 View Test Scenarios (5 tests)

✅ '[example] Pattern matches'
✅ String with regex pattern match - returns true
✅ '[example] No match returns false'
✅ Case sensitive pattern no match - returns false
✅ Empty pattern in string - returns true