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getDataLayerValue — GTM Variable Template for GTM

VARIABLES › GTM
getDataLayerValue CORE GTM
Direct (.tpl) Apply (.tpl)

Retrieves a value from the GTM dataLayer by variable name.

When to Use This

Section titled “When to Use This”
GTM Utilities

Access GTM-specific APIs: dataLayer, debug mode, container settings.

Examples

Section titled “Examples”
Top-level variable
INPUT
DataLayer Variable Name: userId
OUTPUT
12345
Nested variable
INPUT
DataLayer Variable Name: ecommerce.purchase.value
OUTPUT
99.99

GTM Configuration

Section titled “GTM Configuration”

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

Read-only Preview
getDataLayerValue
DataLayer Variable Name
💾 The name of the dataLayer variable to retrieve.

Supports dot notation for nested properties:
  ✓ Top-level variable: "userId", "eventName"
  ✓ Nested property: "user.email", "ecommerce.purchase.value"
  ✓ Array index: "products.0.name"

Supported formats:
  ✓ "String"
Input Setup
Input Function (optional)
⚙️ Optional function to apply to the input before processing.

Supported formats:
   ✓ Function

{{toNumber()}} - convert input to number
{{toLowerCase()}} - convert input to lowercase
{{trim()}} - remove whitespace from input
Result Handling
Output Function (optional)
⚙️ Optional function to apply to the result before returning it.

Supported formats:
   ✓ Function

{{toCamelCase()}} - convert string to camelCase
{{undefinedTo("x")}} - convert undefined value to "x"
{{filter(GreaterThan(10))}} - keep values greater than 10
Section titled “Related Variables”

Same category: GTM

→ document.title → estimateReadingTime → findClosestElement → gaEcommerceEventList → gaLeadGenerationEventList → getCookieValue → getDataLayerByEvent → getDataLayerCurrent → getElementAttribute → getGaMeasurementIds → getLocalStorage → getPersistedDataLayerValue → getRootDomain! → gtmIsDebugMode → gtmIsPreviewMode → hasLocalStorageKey → isGrantedAdPersonalization → isGrantedAdStorage → isGrantedAdUserData → isGrantedAnalyticsStorage → isGrantedFunctionalityStorage → isGrantedPersonalizationStorage → isGrantedSecurityStorage → ⚡ COMMAND TABLE › Lazy (Advanced)

Under the Hood

Section titled “Under the Hood”
📜 View Implementation Code
/**
 * Retrieves a value from the dataLayer
 *
 * @param {string} data.dlVariableName - The dataLayer variable name to retrieve (supports dot notation)
 * @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 variable name before retrieval.
 *
 * @returns {*} The value from the dataLayer, or undefined if not found
 *
 * @framework ggLowCodeGTMKit
 */
const copyFromDataLayer = require('copyFromDataLayer');


const getDataLayerValue = function(variableName) {
    if (!variableName) {
        return undefined;
    }
    return copyFromDataLayer(variableName);
};
const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);
// ===============================================================================
// getDataLayerValue - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const variableName = applyCast(data.pre, data.dlVariableName);
return out(getDataLayerValue(variableName));
// ===============================================================================
// getDataLayerValue() – Apply Mode
// ===============================================================================
/*
return function(variableName) {
   return out(getDataLayerValue(variableName));
};
*/




___WEB_PERMISSIONS___


[
  {
    "instance": {
      "key": {
        "publicId": "read_data_layer",
        "versionId": "1"
      },
      "param": [
        {
          "key": "allowedKeys",
          "value": {
            "type": 1,
            "string": "any"
          }
        }
      ]
    },
    "clientAnnotations": {
      "isEditedByUser": true
    },
    "isRequired": true
  }
]
🧪 View Test Scenarios (5 tests)
✅ '[example] Top-level variable'
✅ '[example] Nested variable'
✅ Test undefined variable returns undefined
✅ Test empty variable name returns undefined
✅ Test with output function transformation