biblatex-csl-converter/src/unescape-csl.ts

a set of converters: biblatex => json, CSL => json, json => biblatex, json => CSL

// If one runs the CSL exporter with escapeText = true, the output from
// citeproc (bibliography and citation entries) will need to be unescaped
// using this function.

export function unescapeCSL(theValue: string): string {
    return theValue
        .replace(/&/g, "&")
        .replace(/</g, "<")
        .replace(/>/g, ">")
        .replace(/'/g, "'")
        .replace(/"/g, """)
}