subtractValues — GTM Variable Template for Number

VARIABLES › NUMBER

subtractValues EXTENDED Number

Direct (.tpl) Apply (.tpl)

Subtracts one number from another. Returns undefined if invalid.

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Examples

Simple subtraction▶ Try

INPUT

Minuend (From): 10
Subtrahend (Amount): 3

OUTPUT

7

String numbers subtracted▶ Try

INPUT

Minuend (From): 20
Subtrahend (Amount): 8

OUTPUT

12

Invalid returns undefined▶ Try

INPUT

Minuend (From): hello
Subtrahend (Amount): 5

OUTPUT

undefined

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GTM Configuration

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subtractValues

Read-Only Try Live

Minuend (From)

💾 The number to subtract from (starting value).

Supported formats:
  ✓ Number

Subtrahend (Amount)

💾 The number to subtract (amount to remove).

Supported formats:
  ✓ Number

Input Setup

Input Function (optional)

⚙️ Optional pre-processing function applied to the minuend before internal logic (e.g., parse string, apply transformations). Internal transformations will still apply afterward.

Result Handling

Output Function (optional)

⚙️ Optional function to apply to the result before returning it (e.g., val => Math.round(val), val => val.toFixed(2) for decimal places). Useful for chaining transformations on the output.

Minuend (From) 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]

Subtrahend (Amount) number

🔗 Result Handling — Chain Variables

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

subtractValues()

+ Chain another variable

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Related Variables

Same category: Number

→ absolute → addValues → calculateDiffRatio → calculateRatioPercentage → ceil → clamp → classifyByThreshold → countDigits → divide → floor → max → min → multiply → parseFloatValue → parseIntValue → squareRoot → toFixed → toInteger

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Under the Hood

📜 View Implementation Code

/**
 * Subtracts the subtrahend from the minuend and returns the result.
 *
 * @param {*} data.min - The number to subtract from (the starting value).
 * @param {*} data.sub - The number to subtract (the amount to remove).
 * @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 min before calculation.
 * 
 * @returns {number|undefined} The result of the subtraction, or undefined if either input is not a valid number.
 *
 * @framework ggLowCodeGTMKit
 */
const makeNumber = require('makeNumber');

const subtractValues = function(minuend, subtrahend) {
    const min = makeNumber(minuend);
    const sub = makeNumber(subtrahend);
    if (min === min && sub === sub) {
        return min - sub;
    }
    return undefined;
};
const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);
// ===============================================================================
// subtractValues - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const processedMinuend = applyCast(data.pre, data.min);
return out(subtractValues(processedMinuend, data.sub));
// ===============================================================================
// subtractValues(...) – Apply Mode
// ===============================================================================
/*
return function(value, subtrahend) {
   subtrahend = data.rp1 ? data.sub : subtrahend;
   return out(subtractValues(value, subtrahend));
};
*/

🧪 View Test Scenarios (5 tests)

✅ '[example] Simple subtraction'
✅ Negative result - should return negative difference
✅ '[example] String numbers subtracted'
✅ Decimal numbers - should handle decimals
✅ '[example] Invalid returns undefined'