dropItemsRight — GTM Variable Template for Array

VARIABLES › ARRAY

dropItemsRight EXTENDED Array

Direct (.tpl) Apply (.tpl)

Removes the last N elements from an array and returns the rest.

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Examples

Drop last 2 items▶ Try

INPUT

Array To Process: [1, 2, 3, 4, 5]
Count: 2

OUTPUT

[1, 2, 3]

Drop all returns empty▶ Try

INPUT

Array To Process: [1, 2, 3]
Count: 10

OUTPUT

[]

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GTM Configuration

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dropItemsRight

Read-Only Try Live

Array To Process

💾 The array to remove items from the end.

Supported formats:
  ✓ Array

Count

💾 The number of items to remove from the end.

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.

Array To Process array

💡 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]

Count number

🔗 Result Handling — Chain Variables

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

dropItemsRight()

+ Chain another variable

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Related Variables

Same category: Array

→ chunk → compact → dropItems → every → filterArray → find → findIndexByCallback → findIndexByRegex → flatten → head → includesAll → includesAny → includesNone → indexOf → join → last → lastIndexOf → reduce → reduceRight → reverse → selectFromArray → some → sort → tail → takeItems → takeItemsRight → uniq → wrapInArray

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Under the Hood

📜 View Implementation Code

/**
 * Removes the last count elements from the array and returns the rest.
 * 
 * @param {Array} data.src - The array to trim.
 * @param {number|string} data.cnt - The number of items to remove from the end.
 * @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 dropping items.
 * 
 * @returns {Array} A new array with the last count items removed, or empty array if input is invalid.
 *
 * @framework ggLowCodeGTMKit
 */
const getType = require('getType');
const Math = require('Math');
const makeNumber = require('makeNumber');

const dropItemsRight = function(arr, count) {
    const cnt = makeNumber(count);
    if (getType(arr) !== 'array' || cnt !== cnt || cnt < 0) {
        return [];
    }
    return arr.slice(0, Math.max(0, arr.length - cnt));
};
const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);
// ===============================================================================
// dropItemsRight - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const value = applyCast(data.pre, data.src);
return out(dropItemsRight(value, data.cnt));
// ===============================================================================
// dropItemsRight(...) – Apply Mode
// ===============================================================================
/*
return function(value, count) {
   count = data.rp1 ? data.cnt : count;
   return out(dropItemsRight(value, count));
};
*/

🧪 View Test Scenarios (5 tests)

✅ '[example] Drop last 2 items'
✅ String count parameter - converts to number and drops elements
✅ '[example] Drop all returns empty'
✅ Negative count - returns empty array
✅ Non-array input - returns empty array