Small Snippet to parse Macros on GTM Debug Interface

gtm-debug-ui-macro-parser.js

// Small Snippet to Parse GTM Macros on GTM Debug Interface
// Idea From Simo's Post: #GTMTips: The Mysterious .macro() Call In Custom HTML Tags
// URL: https://www.simoahava.com/gtm-tips/mysterious-macro-call-custom-html-tags/

// Current Version, does not take care of current variable type, all is replaces as str.
(function() {
    const iframe = document.querySelector('iframe[src="about:blank"]');
    iframe.contentDocument.querySelectorAll('.CodeMirror-code').forEach(function(e) {
        if (e.querySelectorAll('.CodeMirror-line').length > 0) {
            let _code = [...e.querySelectorAll('pre.CodeMirror-line')].map(function(e) {
                return e.textContent;
            }).join('');
            let match = _code.match(/google_tag_manager\[\"[A-Z]*\-[A-Z0-9]*\"\]\.macro\([0-9*]{1,5}\)/);
            if (match) {
                const regex = /google_tag_manager\[\"[A-Z]*\-[A-Z0-9]*\"\]\.macro\([0-9*]{1,5}\)/gm;
                let str = _code;
                let m;
                while ((m = regex.exec(str)) !== null) {
                    if (m.index === regex.lastIndex) {
                        regex.lastIndex++;
                    }
                    m.forEach((match)=>{
                        const value = eval("parent." + match);
                        str = str.replace(match, `"${value}"`);
                    }
                    );
                }
                iframe.contentDocument.querySelectorAll('.CodeMirror-code')[0].innerText = str;
            }
        }
    });
}
)();