Function addCandidate

apps/json-format/content-script.js:1201–1207

        let candidates = [];
        let seen = new Set();
        let addCandidate = text => {
            text = (text || '').trim();
            if (text && !seen.has(text)) {
                seen.add(text);
                candidates.push(text);
            }
        };
        let isVisibleElement = elm => elm && elm.nodeType === Node.ELEMENT_NODE && (elm.offsetHeight + elm.offsetWidth !== 0);

        addCandidate(dom && dom.textContent);