getMonthName — GTM Variable Template for Date

VARIABLES › DATE

getMonthName CORE Date

Direct (.tpl) Apply (.tpl)

Returns the full name of the month. 0 = January, 11 = December.

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When to Use This

Date Formatting

Format and transform date values into human-readable or machine-readable strings.

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Examples

Index 0 returns January▶ Try

INPUT

Month Index: 0

OUTPUT

January

Index 11 returns December▶ Try

INPUT

Month Index: 11

OUTPUT

December

Invalid index returns undefined▶ Try

INPUT

Month Index: 12

OUTPUT

undefined

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GTM Configuration

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

getMonthName

Read-Only Try Live

Month Index

💾 An integer representing the month of the year (0 = January, 1 = February, etc.).

Supported formats:
  ✓ Number
  ✓ 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.

Month Index number

💡 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.

getMonthFullName()

+ Chain another variable

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Related Variables

Same category: Date

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

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Under the Hood

📜 View Implementation Code

/**
* Returns the full name of the month based on the given integer where 0 = January, 1 = February, etc.
* 
* @param {number|string} data.src - An integer representing the month of the year (0 to 11).
* @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 conversion.
* 
* @returns {string|undefined} The full name of the month (e.g., "January", "February", etc.), or undefined if the index is invalid.
*
* @framework ggLowCodeGTMKit
*/
const makeNumber = require('makeNumber');

const getMonthFullName = function(monthInt) {
   const month = makeNumber(monthInt);
   const monthList = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
   return monthList[month];
};

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

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

🧪 View Test Scenarios (5 tests)

✅ '[example] Index 0 returns January'
✅ '[example] Index 11 returns December'
✅ String number month index - converts and returns month name
✅ '[example] Invalid index returns undefined'
✅ Invalid string input - returns undefined