getDataLayerByEvent — GTM Variable Template for GTM

getDataLayerByEvent CORE GTM

Retrieves the current dataLayer event object from window.dataLayer, or a first-level property value if specified. ↪️ Full Object: event object or {} if not found. ↪️ DataLayer Variable: property value or undefined if not found. ⚡ Result is cached

When to Use This

GTM Utilities

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

GTM Configuration

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getDataLayerByEvent

Event Name

Use regex matching for event name

Return Type

Property Key

Result Handling

Output Function (optional)

Under the Hood

📜 View Implementation Code

/**
 * Retrieves the most recent occurrence of a given event in window.dataLayer or a specific property.
 * Searches up to 1 level deep to handle wrapped structures.
 *
 * @param {string} data.evt - The event name to search for (Direct mode).
 * @param {boolean} [data.rgx] - Use regex matching for event name. Default: exact match.
 * @param {string} [data.add] - Mode: "fob" for full object, "dlv" for dataLayer variable.
 * @param {string} [data.key] - Property name to extract (when add="dlv").
 * @param {Function|string} [data.out] - Optional output handler.
 *
 * @returns {Object|*} Full object (or {}) when fob, property value (or undefined) when dlv.
 *
 * @framework ggLowCodeGTMKit
 */
const copyFromWindow = require('copyFromWindow');
const copyFromDataLayer = require('copyFromDataLayer');
const templateStorage = require('templateStorage');
const EVENT_ID_KEY = 'gtm.uniqueEventId';
const gtmId = copyFromDataLayer(EVENT_ID_KEY);
const getEventObjectByName = function(eventName, useRegex) {
    if (!gtmId || !eventName) return undefined;

    const CACHE_KEY = 'dlEvtByName';
    const cacheKey = CACHE_KEY + '_' + eventName + '_' + gtmId;
    const cache = templateStorage.getItem(cacheKey);
    if (cache && cache.obj !== undefined && cache.obj !== '') {
        return cache.obj;
    }

    const dataLayer = copyFromWindow('dataLayer');
    if (!dataLayer) return undefined;

    const cacheAndReturn = function(obj) {
        templateStorage.setItem(cacheKey, { obj: obj });
        return obj;
    };

    const eventMatches = function(evt) {
        if (!evt) return false;
        if (useRegex) {
            return evt.match(eventName);
        }
        return evt === eventName;
    };

    const findEventObject = function(item) {
        if (!item || typeof item !== 'object') return undefined;

        if (eventMatches(item.event)) {
            const itemId = item[EVENT_ID_KEY];
            if (itemId && itemId <= gtmId) {
                return item;
            }
        }

        for (let key in item) {
            if (!item.hasOwnProperty(key)) continue;
            const nested = item[key];
            if (nested && typeof nested === 'object' && eventMatches(nested.event)) {
                const nestedId = nested[EVENT_ID_KEY];
                if (nestedId && nestedId <= gtmId) {
                    return nested;
                }
            }
        }

        return undefined;
    };

    for (let i = dataLayer.length - 1; i >= 0; i--) {
        const item = dataLayer[i];
        if (!item) continue;

        const found = findEventObject(item);
        if (found) {
            return cacheAndReturn(found);
        }
    }

    return cacheAndReturn(undefined);
};
const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);
// ===============================================================================
// getDataLayerByEvent - Dire

getDataLayerByEvent — GTM Variable Template for GTM

When to Use This

GTM Configuration

Related Variables

Under the Hood