applyChain — GTM Variable Template for Value

VARIABLES › VALUE

applyChain CORE Value

Direct (.tpl) Apply (.tpl)

Applies a chain of functions sequentially to a value.

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When to Use This

Value Utilities

Handle edge cases — defaults for undefined/null, type checks, coercion.

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Examples

Single function chain▶ Try

INPUT

Input Value: 10
Functions: [{func: x => x * 2}]

OUTPUT

20

Multiple function chain▶ Try

INPUT

Input Value: 5
Functions: [{func: x => x * 2}, {func: x => x + 10}, {func: x => x / 5}]

OUTPUT

4

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GTM Configuration

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applyChain

Read-Only Try Live

Input Value

💾 The initial value to which the functions will be applied.

Supported formats:
  ✓ Any

Functions

⊖

Add Row

Input Value any

💡 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]

Functions list

✕

+ Add Row

🔗 Result Handling — Chain Variables

Chain apply-mode variables to the output. Each variable receives the result of the previous one.

applyChain()

+ Chain another variable

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Related Variables

Same category: Value

→ NaN → apply → emptyArray → emptyObject → emptyObjectArray → emptyString → false → falseTo → falsyTo → filterValue → getLength → getType → identity → mapTruthiness → not → null → nullTo → parseValue → regexTableLookupAll → regexTableLookupCallback → true → undefinedTo → zero

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Under the Hood

📜 View Implementation Code

/**
* Applies a list of functions sequentially to an input value.
* 
* @param {*} data.src - The initial value to which the functions will be applied.
* @param {Array} data.lst - An array of function objects to be applied sequentially.
* 
* @returns {*} The result after all functions have been applied to the input.
*
* @framework ggLowCodeGTMKit
*/

const applyChain = function(input, functionList) {
   return functionList.reduce((acc, fnObj) => {
       if (typeof fnObj.func === 'function') {
           return fnObj.func(acc);
       }
       return acc;
   }, input);
};

// ===============================================================================
// applyChain - Direct mode only
// ===============================================================================
return applyChain(data.src, data.lst);

// ===============================================================================
// applyChain(...) – Apply Mode
// ===============================================================================
/*
return function(input) {
   return applyChain(input, data.lst) ;
};
*/

🧪 View Test Scenarios (5 tests)

✅ '[example] Single function chain'
✅ '[example] Multiple function chain'
✅ Empty function list returns original value
✅ Function list with invalid function object - skips invalid and continues
✅ String transformation chain - applies string operations