get-section-fields.js

var entryTypeUrls = [];
var sections = {};
var responses = [];

fetch(window.Craft.baseCpUrl + '/settings/sections/')
	  .then(function(response) {
	    return response.text();
	  })
	  .then(function(html) {
	    var parser = new DOMParser();
	    var htmlResponse = parser.parseFromString(html, 'text/html');
	    var entryTypes = htmlResponse.querySelectorAll('#sections tr a[href*="entrytypes/"]');
	    if (entryTypes.length) {
	      entryTypes.forEach(function(entryType) {
	        entryTypeUrls.push([entryType.href]);
	      });
	    }
	  })
		.then(done => {
			entryTypeUrls.forEach(entryTypeUrl => {
				return getEntryTypeFields(entryTypeUrl);
            });
        });

function getEntryTypeFields(url) {
	fetch(url)
      .then(function(response, url) {
			responses.push(response.status);
            return response.text();
          })
          .then(function(html) {
            var parser = new DOMParser();
            var htmlResponse = parser.parseFromString(html, 'text/html');
			var handle = htmlResponse.querySelector('#handle');
            var fieldTabsEl = htmlResponse.querySelectorAll('.fld-tabs .fld-tab');
			var fieldTabs = {};

			if (fieldTabsEl.length) {
              fieldTabsEl.forEach(function(fieldTab) {

				var tabFields = [];
                fieldTabs = {
					...fieldTabs,
					[fieldTab.querySelector('.tab span').textContent]: tabFields 
                }
				fieldTab.querySelectorAll('.fld-field > span').forEach(field => {
					tabFields.push(field.title);
                });

              });

			if(handle) {
				sections = {
					...sections,
                	[handle.value]: fieldTabs
                }
    		}

            
            }
          })
		.then(ready => {				
            responses.length === entryTypeUrls.length && responses.map((response, idx) => {
                if( response === 200 && idx === entryTypeUrls.length-1 ) {
                  var responseEl = document.createElement("code"); 
				  responseEl.style = 
					'position: fixed;' +
					'padding: 32px;' +
					'bottom: 0;' +
					'z-index: 500;' +
					'background: black;' +
					'color: white;' +
					'max-height: calc(100vh - 64px);' +
					'overflow: auto;';

                   	for (let [key, values] of Object.entries(sections).sort()) {
					  let sectionHandle = key;
					  let sectionFields = [];
    				  for (let fields of Object.entries(values).sort()) {
						sectionFields.push(fields);
                      }	
                      responseEl.innerHTML +=
						'<span style="color: tomato;">Type: ' + sectionHandle + '</span><br / >' +
						sectionFields.map(sectionField => {
							return ( 
								'\xa0\xa0' + '<span style="color: tan;">Tab: ' + sectionField[0] + '</span><br />' +
								sectionField[1].map(fields => {
									return '\xa0\xa0\xa0\xa0' + fields + '<br />'
                                }).join('')
							);
						}).join('') + '<br />';
                    }

                    document.body.appendChild(responseEl); 
                }
            });
    	});
}