louis-e/arnis · warning · Error

empty -- nothing to parse

Error message

empty -- nothing to parse

What it means

FormatSniffer._is_wkt attempts to parse the sniffed input as WKT. When the input data is the empty string, there is nothing to parse, so the function throws 'empty -- nothing to parse' rather than returning null like other parse failures. Callers must treat empty input as a distinct error case from 'not WKT'.

Source

Thrown at src/gui/js/bbox.js:118

            // try JSON
            var json = JSON.parse(this.data);

            // try GeoJSON
            var parsed_data = new L.geoJson(json)

        } catch (err) {

            return null;

        }

        this.parse_type = "geojson";
        return parsed_data;
    };

    FormatSniffer.prototype._is_wkt = function () {
        if (this.data === "") {
            throw new Error("empty -- nothing to parse");
        }

        try {
            var parsed_data = new Wkt.Wkt(this.data);
        } catch (err) {
            return null;
        }

        this.parse_type = "wkt";
        return parsed_data;
    };

    FormatSniffer.prototype._sniffFormat = function () {

        var parsed_data = null;
        var fail = false;
        try {
            var next = true;

View on GitHub (pinned to 34048924d9)

Solutions

1. Guard before sniffing: check this.data === "" (or trim() === "") and return null / a 'no input' result instead of invoking _is_wkt.
2. Wrap the sniffing call in try/catch and treat the 'empty -- nothing to parse' message as 'no data provided' rather than a parse failure.
3. Fix the UI layer to disable sniffing/parse until the user supplies non-empty input.

Example fix

// before
var format = sniffer._is_wkt(); // throws on empty input
// after
if (!sniffer.data || sniffer.data.trim() === "") {
    return null; // nothing to parse
}
var format = sniffer._is_wkt();

if (typeof data !== 'string' || data.trim() === '') {
    return null; // nothing to sniff
}

function isNonEmptyString(v) {
  return typeof v === 'string' && v.trim().length > 0;
}

try {
  return sniffer._is_wkt();
} catch (err) {
  if (err && err.message === 'empty -- nothing to parse') return null;
  throw err;
}

When it happens

Trigger: Calling _is_wkt (or the format-sniffing entry point that dispatches to it) on a FormatSniffer whose data property is "" — e.g. sniffing an empty file, an empty textarea, or an empty pasted string.

Common situations: User submits a bounding-box/GUI form without entering any data; a file input reads a zero-byte file; upstream code trimmed whitespace-only input down to "" before sniffing; automated tests passing empty fixtures.

AI-assisted analysis of louis-e/arnis@34048924d9 (2026-09-03). Data as JSON: /api/errors/078a855da5e3593b. Report an issue: GitHub.