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reverse — GTM Variable Template for Array

VARIABLES › ARRAY
reverse EXTENDED Array
Direct (.tpl) Apply (.tpl)

Returns a new array with the elements in reverse order without modifying the original.

When to Use This

Section titled “When to Use This”

Examples

Section titled “Examples”
Reverse array
INPUT
Array To Reverse: [1, 2, 3, 4, 5]
OUTPUT
[5, 4, 3, 2, 1]
Non-array returns empty
INPUT
Array To Reverse: not an array
OUTPUT
[]

Live Sandbox

Section titled “Live Sandbox”

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

reverse
Array To Reverse
💾 The array to reverse the order of elements.

Supported formats:
  ✓ Array
Input Setup
Input Function (optional)
⚙️ Optional pre-processing function applied to the input before internal logic (e.g., convert object to string, normalize case). Internal transformations such as case handling will still apply afterward.
Result Handling
Output Function (optional)
⚙️ Optional function to apply to the result before returning it (e.g., str => str + ' €', val => val !== undefined for boolean conversion). Useful for chaining transformations on the output.
Array To Reverse array
💡 Type any text to see the result update live
🎯 Using special value — click input to type instead
Test with:
Falsy
Truthy
🔗 Result Handling — Chain Variables
Chain apply-mode variables to the output. Each variable receives the result of the previous one.
reverse()
Section titled “Related Variables”

Same category: Array

→ chunk → compact → dropItems → dropItemsRight → every → filterArray → find → findIndexByCallback → findIndexByRegex → flatten → head → includesAll → includesAny → includesNone → join → last → lastIndexOf → map → reduce → reduceRight → selectFromArray → some → sort → tail → takeItems → takeItemsRight → uniq → wrapInArray → ⚡ ARRAY › From Indexed Values → ⚡ ARRAY › From Values

Under the Hood

Section titled “Under the Hood”
📜 View Implementation Code
/**
* Returns a new array with the elements in reverse order.
*
* @param {Array} data.src - The array to reverse.
* @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 reversing.
*
* @returns {Array} A new array with reversed elements, or an empty array if input is invalid.
*
* @framework ggLowCodeGTMKit
*/
const getType = require('getType');


const reverse = function(arr) {
   if (getType(arr) !== 'array') {
       return [];
   }
   return arr.slice().reverse();
};


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


// ===============================================================================
// reverse - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const value = applyCast(data.pre, data.src);
return out(reverse(value));


// ===============================================================================
// reverse() – Apply Mode
// ===============================================================================
/*
return function(value) {
  return out(reverse(value));
};
*/
🧪 View Test Scenarios (5 tests)
✅ '[example] Reverse array'
✅ Array with strings - should reverse order
✅ Array with single element - should return same element
✅ Empty array - should return empty array
✅ '[example] Non-array returns empty'