function enter()

in modules/behavior/hover.js [125:184]

• 46 lines of code
• 26 McCabe index (conditional complexity)

        function enter(datum) {
            if (datum === _target) return;
            _target = datum;

            _selection.selectAll('.hover')
                .classed('hover', false);
            _selection.selectAll('.hover-suppressed')
                .classed('hover-suppressed', false);

            // What are we hovering over?
            var entity, selector;
            if (datum && datum.__featurehash__) {
                entity = datum;
                selector = '.data' + datum.__featurehash__;

            } else if (datum instanceof qaError) {
                entity = datum;
                selector = '.' + datum.service + '.error_id-' + datum.id;

            } else if (datum instanceof osmNote) {
                entity = datum;
                selector = '.note-' + datum.id;

            } else if (datum instanceof osmEntity) {
                entity = datum;
                selector = '.' + entity.id;
                if (entity.type === 'relation') {
                    entity.members.forEach(function(member) { selector += ', .' + member.id; });
                }
            } else if (datum && datum.properties && (datum.properties.entity instanceof osmEntity)) {
                entity = datum.properties.entity;
                selector = '.' + entity.id;
                if (entity.type === 'relation') {
                    entity.members.forEach(function(member) { selector += ', .' + member.id; });
                }
            }

            var mode = context.mode();

            // Update hover state and dispatch event
            if (entity && entity.id !== _newNodeId) {
                // If drawing a way, don't hover on a node that was just placed. #3974

                if ((mode.id === 'draw-line' || mode.id === 'draw-area') && !_newNodeId && entity.type === 'node') {
                    _newNodeId = entity.id;
                    return;
                }

                var suppressed = (_altDisables && d3_event && d3_event.altKey) ||
                    (entity.type === 'node' && _ignoreVertex && !allowsVertex(entity)) ||
                    !modeAllowsHover(entity);
                _selection.selectAll(selector)
                    .classed(suppressed ? 'hover-suppressed' : 'hover', true);

                dispatch.call('hover', this, !suppressed && entity);

            } else {
                dispatch.call('hover', this, null);
            }
        }