@vectara/vectara-ui/lib/utils/citations/reorderCitations.js

Vectara's design system, codified as a React and Sass component library

export const reorderCitations = (unorderedSummary) => {
    const allCitations = unorderedSummary.match(/\[\d+\]/g) || [];
    const uniqueCitations = [...new Set(allCitations)];
    const citationToReplacement = {};
    uniqueCitations.forEach((citation, index) => {
        citationToReplacement[citation] = `[${index + 1}]`;
    });
    return unorderedSummary.replace(/\[\d+\]/g, (match) => citationToReplacement[match]);
};