hasNested — GTM Variable Template for Object

VARIABLES › OBJECT

hasNested EXTENDED Object

Direct (.tpl) Apply (.tpl)

Checks if a nested property exists in an object using a path.

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Examples

Nested property exists▶ Try

INPUT

Object to Check: {a: {b: {c: 'value'}}}
Property Path: a.b.c

OUTPUT

true

Nested property missing▶ Try

INPUT

Object to Check: {a: {b: {}}}
Property Path: a.b.c

OUTPUT

false

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GTM Configuration

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hasNested

Read-Only Try Live

Object to Check

💾 The object to check for the nested property.

Supported formats:
  ✓ Object variable: {{myObject}}
  ✓ Object literal

Property Path

💾 The path to the nested property. Can use dot notation or array format.

Supported formats:
  ✓ String (dot notation): "user.profile.name"
  ✓ Array: ["user", "profile", "name"]

Input Setup

Input Function (optional)

⚙️ Optional pre-processing function applied to the object before checking (e.g., normalize object structure, parse JSON).

Result Handling

Output Function (optional)

⚙️ Optional function to apply to the boolean result before returning it (e.g., val => !val to invert, val => val ? 'exists' : 'missing'). Useful for chaining transformations on the output.

Object to Check object

💡 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]

Property Path array

🔗 Result Handling — Chain Variables

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

hasNested()

+ Chain another variable

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Related Variables

Same category: Object

→ applyFromObject → assignDefaults → assignDefaultsDeep → assignObjects → assignObjectsFromPairs → entries → getKeys → getValue → getValueByPath → has → hasKeyEqualTo → mergeConcat → mergeConcatDeep → omit → parseJsonString → pick → pickNested → set → toObjectPairs → values → zipObject

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Under the Hood

📜 View Implementation Code

/**
 * Checks if a nested property exists in an object using a path string or array.
 *
 * @param {Object} data.src - The object to check.
 * @param {string|string[]} data.pth - The path to the property (e.g., "a.b.c" or ["a", "b", "c"]).
 * @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 checking.
 * 
 * @returns {boolean} Returns true if the nested property exists, false otherwise.
 *
 * @framework ggLowCodeGTMKit
 */
const getType = require('getType');

const hasNested = function(obj, path) {
    if (getType(obj) !== 'object' || obj === null) {
        return false;
    }
    
    const pathParts = getType(path) === 'array' 
        ? path.map(function (part) { return part.toString(); }) 
        : path.split('.');
    
    let current = obj;
    let index = 0;
    const length = pathParts.length;
    
    while (current != null && index < length) {
        if (!current.hasOwnProperty(pathParts[index])) {
            return false;
        }
        current = current[pathParts[index++]];
    }
    
    return index === length;
};
const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);
// ===============================================================================
// hasNested - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const value = applyCast(data.pre, data.src);
return out(hasNested(value, data.pth));
// ===============================================================================
// hasNested(...) – Apply Mode
// ===============================================================================
/*
return function(obj, path) {
   path = data.rp1 ? data.pth : path;
   return out(hasNested(obj, path));
};
*/

🧪 View Test Scenarios (5 tests)

✅ '[example] Nested property exists'
✅ '[example] Nested property missing'
✅ Test with array path format
✅ Test property exists with undefined value
✅ Test with non-object input returns false