function tagsForConnectionNodeIfAllowed()

in modules/validations/crossing_ways.js [130:203]
53 lines of code
31 McCabe index (conditional complexity)

    function tagsForConnectionNodeIfAllowed(entity1, entity2, graph) {
        var featureType1 = getFeatureType(entity1, graph);
        var featureType2 = getFeatureType(entity2, graph);

        var geometry1 = entity1.geometry(graph);
        var geometry2 = entity2.geometry(graph);
        var bothLines = geometry1 === 'line' && geometry2 === 'line';

        if (featureType1 === featureType2) {
            if (featureType1 === 'highway') {
                var entity1IsPath = osmPathHighwayTagValues[entity1.tags.highway];
                var entity2IsPath = osmPathHighwayTagValues[entity2.tags.highway];
                if ((entity1IsPath || entity2IsPath) && entity1IsPath !== entity2IsPath) {
                    // one feature is a path but not both

                    var roadFeature = entity1IsPath ? entity2 : entity1;
                    if (nonCrossingHighways[roadFeature.tags.highway]) {
                        // don't mark path connections with certain roads as crossings
                        return {};
                    }
                    var pathFeature = entity1IsPath ? entity1 : entity2;
                    if (['marked', 'unmarked'].indexOf(pathFeature.tags.crossing) !== -1) {
                        // if the path is a crossing, match the crossing type
                        return bothLines ? { highway: 'crossing', crossing: pathFeature.tags.crossing } : {};
                    }
                    // don't add a `crossing` subtag to ambiguous crossings
                    return bothLines ? { highway: 'crossing' } : {};
                }
                return {};
            }
            if (featureType1 === 'waterway') return {};
            if (featureType1 === 'railway') return {};

        } else {
            var featureTypes = [featureType1, featureType2];
            if (featureTypes.indexOf('highway') !== -1) {
                if (featureTypes.indexOf('railway') !== -1) {
                    if (!bothLines) return {};

                    var isTram = entity1.tags.railway === 'tram' || entity2.tags.railway === 'tram';

                    if (osmPathHighwayTagValues[entity1.tags.highway] ||
                        osmPathHighwayTagValues[entity2.tags.highway]) {

                        // path-tram connections use this tag
                        if (isTram) return { railway: 'tram_crossing' };

                        // other path-rail connections use this tag
                        return { railway: 'crossing' };
                    } else {
                        // path-tram connections use this tag
                        if (isTram) return { railway: 'tram_level_crossing' };

                        // other road-rail connections use this tag
                        return { railway: 'level_crossing' };
                    }
                }

                if (featureTypes.indexOf('waterway') !== -1) {
                    // do not allow fords on structures
                    if (hasTag(entity1.tags, 'tunnel') && hasTag(entity2.tags, 'tunnel')) return null;
                    if (hasTag(entity1.tags, 'bridge') && hasTag(entity2.tags, 'bridge')) return null;

                    if (highwaysDisallowingFords[entity1.tags.highway] ||
                        highwaysDisallowingFords[entity2.tags.highway]) {
                        // do not allow fords on major highways
                        return null;
                    }
                    return bothLines ? { ford: 'yes' } : {};
                }
            }
        }
        return null;
    }