has — GTM Variable Template for Object

VARIABLES › OBJECT

has EXTENDED Object

Direct (.tpl) Apply (.tpl)

Checks if an object has a specific key.

---

---

Examples

Key exists returns true▶ Try

INPUT

Object to Check: {name: "John", age: 30}
Property Key: name

OUTPUT

true

Key missing returns false▶ Try

INPUT

Object to Check: {name: "John", age: 30}
Property Key: email

OUTPUT

false

---

GTM Configuration

This is what you'll see when you open this variable in Google Tag Manager. Hover the icons for details.

has

Read-Only Try Live

Object to Check

💾 The object to check for the property.

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

Property Key

💾 The name of the property to check for. Checks own properties only (not inherited from prototype).

Supported formats:
  ✓ String: "name", "userId"

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 Key string

🔗 Result Handling — Chain Variables

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

has()

+ Chain another variable

---

Related Variables

Same category: Object

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

---

Under the Hood

📜 View Implementation Code

/**
 * Checks if an object contains a top-level own property with the given key.
 *
 * @param {Object} data.src - The object to check.
 * @param {string} data.key - The name of the property to check for.
 * @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 object has the specified key (regardless of value).
 *
 * @framework ggLowCodeGTMKit
 */
const has = function(obj, key) {
    if (obj == null || typeof obj !== 'object' || typeof key !== 'string') {
        return false;
    }
    return obj.hasOwnProperty(key);
};
const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);
// ===============================================================================
// has - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const value = applyCast(data.pre, data.src);
return out(has(value, data.key));
// ===============================================================================
// has(...) – Apply Mode
// ===============================================================================
/*
return function(obj, key) {
   key = data.rp1 ? data.key : key;
   return out(has(obj, key));
};
*/

🧪 View Test Scenarios (5 tests)

✅ '[example] Key exists returns true'
✅ '[example] Key missing returns false'
✅ Null object returns false
✅ Non-string key returns false
✅ Object has key with undefined value