getDayNameShort — GTM Variable Template for Date

VARIABLES › DATE

getDayNameShort CORE Date

Direct (.tpl) Apply (.tpl)

Returns the abbreviated name of the day of the week. 0 = Mon, 6 = Sun.

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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 Mon▶ Try

INPUT

Day Index: 0

OUTPUT

Mon

Invalid index returns undefined▶ Try

INPUT

Day Index: 10

OUTPUT

undefined

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GTM Configuration

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getDayNameShort

Read-Only Try Live

Day Index

💾 An integer representing the day of the week (0 = Monday, 1 = Tuesday, 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.

Day 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.

getDayName()

+ Chain another variable

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Related Variables

Same category: Date

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

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Under the Hood

📜 View Implementation Code

/**
* Returns the abbreviated name of the day of the week based on the given integer where 0 = Monday, 1 = Tuesday, etc.
* 
* @param {number|string} data.src - An integer representing the day of the week (0 to 6).
* @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 abbreviated name of the day (e.g., "Mon", "Tues", etc.), or undefined if the index is invalid.
*
* @framework ggLowCodeGTMKit
*/
const makeNumber = require('makeNumber');

const getDayName = function(dayInt) {
   const day = makeNumber(dayInt);
   const dayList = ["Mon", "Tues", "Wed", "Thu", "Fri", "Sat", "Sun"];
   return dayList[day];
};

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

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

// ===============================================================================
// getDayName() – Apply Mode: runtime parameter
// ===============================================================================
/*
return function(value) {
  return out(getDayName(value));
};
*/

🧪 View Test Scenarios (4 tests)

✅ '[example] Index 0 returns Mon'
✅ Valid day index 3 - returns Thursday
✅ Valid day index 6 - returns Sunday
✅ '[example] Invalid index returns undefined'