_getCandidateString(msgPath) {
        // Our default string mode is "dot" for dot-notation, e.g. $.something.like.this used in the backend
        // Both jsonpath's dot-notation and bracket-notation start with '$' E.g.: $.store.book.title or $['store']['book']['title']
        // While bracket-notation allows any Unicode characters in keys (i.e. for themes / fulltext mode) E.g. $['Read more']
        // dot-notation allows only word characters in keys for backend messages (that is \w or [A-Za-z0-9_] in RegExp)
        let jsonPath = `$.${msgPath}`;
        let fallback = null;

        if (this._stringMode === 'fulltext') {
            jsonPath = jp.stringify(['$', msgPath]);
            // In fulltext mode we can use the passed string as a fallback
            fallback = msgPath;
        }

        try {
            return jp.value(this._strings, jsonPath) || fallback;
        } catch (err) {
            this._handleInvalidKeyError(msgPath, err);
        }
    }
Do the lookup within the JSON file using jsonpath

@param {String} msgPath