reverseDateSlash — GTM Variable Template for Date

VARIABLES › DATE

reverseDateSlash EXTENDED Date

Direct (.tpl) Apply (.tpl)

Reverses a date string between "dd/mm/yyyy" and "yyyy/mm/dd" formats.

---

---

Examples

Reverse dd/mm/yyyy▶ Try

INPUT

Date String: 25/12/2024

OUTPUT

2024/12/25

Reverse yyyy/mm/dd▶ Try

INPUT

Date String: 2025/01/01

OUTPUT

01/01/2025

---

GTM Configuration

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

reverseDateSlash

Read-Only Try Live

Date String

💾 The date string to reverse, using slash separators.

Supported formats:
  ✓ String

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.

Date String 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.

reverseDateSlash()

+ Chain another variable

---

Related Variables

Same category: Date

→ calculateDaysDifference → currentTimestamp → getDayIndexFromDateString → getDayName → getDayNameFromDateString → getDayNameShort → getMonthName → getMonthNameShort → reverseDateCompactDay1st → reverseDateCompactYear1st → timestampToDayIndex

---

Under the Hood

📜 View Implementation Code

/**
* Reverse a date string between "dd/mm/yyyy" and "yyyy/mm/dd" formats.
* 
* @param {string} data.src - The date string to reverse, using slash separators.
* @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 {string|undefined} The reversed date string, or undefined if the input is invalid.
*
* @framework ggLowCodeGTMKit
*/
const reverseDateSlash = function(date) {
   if (typeof date === 'string') {
       const parts = date.split('/');
       if (parts.length === 3) {
           return parts.reverse().join('/');
       }
   }
   return undefined;
};

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

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

🧪 View Test Scenarios (5 tests)

✅ '[example] Reverse dd/mm/yyyy'
✅ '[example] Reverse yyyy/mm/dd'
✅ Valid date with leading zeros - reverses correctly
✅ Invalid format without slashes - returns undefined
✅ Invalid format with wrong number of parts - returns undefined