basicDateToExtended — GTM Variable Template for Date

VARIABLES › DATE

basicDateToExtended EXTENDED Date

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

Converts a basic ISO date (YYYYMMDD) to extended format (YYYY-MM-DD).

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When to Use This

Date Formatting

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

Type Conversion

Safely convert between data types — strings, numbers, booleans, arrays, objects.

Date & Time

Calculate durations, differences, and time-based operations on date values.

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Examples

Basic to extended ISO date▶ Try

INPUT

Compact Date: 20241225

OUTPUT

2024-12-25

Invalid returns undefined▶ Try

INPUT

Compact Date: 2024122

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.

basicDateToExtended

Read-Only Try Live

Compact Date

💾 The compact date string in "yyyymmdd" format.

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.

Compact Date 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.

basicDateToExtended()

+ Chain another variable

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Related Variables

Same category: Date

→ addDays → calculateDaysDifference → calculateLeadTime → currentTimestamp → dateToUnixTimestamp → daysToMilliseconds → extendedDateToBasic → getDayIndexFromDateString → getDayName → getDayNameFromDateString → getDayNameShort → getHourOfDay → getMonthName → getMonthNameShort → hoursToMilliseconds → isBusinessHours → isWeekend → millisecondsToDays → millisecondsToHours → millisecondsToMinutes → millisecondsToSeconds → minutesToMilliseconds → reverseDateCompactDay1st → reverseDateCompactYear1st → reverseDateSlash → secondsToMilliseconds → subtractDays → timestampToDayIndex → unixTimestampToDate

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Under the Hood

📜 View Implementation Code

/**
* Convert a basic ISO 8601 date (yyyymmdd) to extended format (yyyy-mm-dd).
*
* @param {string} data.src - The compact date string in "yyyymmdd" format.
* @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 extended date string in "yyyy-mm-dd" format, or undefined if input is invalid.
*
* @framework ggLowCodeGTMKit
*/
const basicDateToExtended = function(date) {
   if (typeof date !== 'string' || date.length !== 8) { return undefined; }
   const year = date.slice(0, 4);
   const month = date.slice(4, 6);
   const day = date.slice(6, 8);
   return year + "-" + month + "-" + day;
};

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

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

🧪 View Test Scenarios (5 tests)

✅ '[example] Basic to extended ISO date'
✅ Valid date with January first - converts correctly
✅ Valid date end of year - converts correctly
✅ '[example] Invalid returns undefined'
✅ Non-string input - returns undefined