How to use the d3-selection.event.keyCode function in d3-selection

.on('keydown', function() {
                // if user presses enter, and combobox is not active, accept edits..
                if (d3_event.keyCode === 13 && d3_select('.combobox').empty()) {
                    context.enter(modeBrowse(context));
                }
            });
    }

function keydown() {
            if (!(d3_event.keyCode === 13 && d3_event.metaKey)) return;

            var osm = services.osm;
            if (!osm) return;

            var hasAuth = osm.authenticated();
            if (!hasAuth) return;

            if (!_note.newComment) return;

            d3_event.preventDefault();

            d3_select(this)
                .on('keydown.note-input', null);

            // focus on button and submit
            window.setTimeout(function() {

function keydown() {
            var shown = !container.selectAll('.combobox').empty();
            var tagName = input.node() ? input.node().tagName.toLowerCase() : '';

            switch (d3_event.keyCode) {
                case 8:   // ⌫ Backspace
                case 46:  // ⌦ Delete
                    d3_event.stopPropagation();
                    _selected = null;
                    render();
                    input.on('input.combo-input', function() {
                        var start = input.property('selectionStart');
                        input.node().setSelectionRange(start, start);
                        input.on('input.combo-input', change);
                    });
                    break;

                case 9:   // ⇥ Tab
                    accept();
                    break;

function keydown() {
            if (d3_event.keyCode === 27) {  // escape
                search.node().blur();
            }
        }

function pushMore() {
            if (d3_event.keyCode === 9 && !d3_event.shiftKey &&
                list.selectAll('li:last-child input.value').node() === this) {
                addTag();
            }
        }

select(document).on(`keydown.${id}`, () => {
      const {active, results} = this.state;
      const key = event.keyCode;

      const DOWN = 40,
            ENTER = 13,
            ESC = 27,
            S = 83,
            UP = 38;

      if (primary && !active && key === S && !["input", "textarea"].includes(event.target.tagName.toLowerCase()) && !event.target.className.includes("ql-editor")) {
        event.preventDefault();
        this.onToggle.bind(this)();
      }
      else if (active && key === ESC && event.target === this.input) {
        event.preventDefault();
        this.onToggle.bind(this)();
      }
      else if (active && event.target === this.input) {

select(document).on(`keydown.${id}`, () => {

      const {router} = this.context;
      const {active, results} = this.state;
      const key = event.keyCode;

      const DOWN = 40,
            ENTER = 13,
            ESC = 27,
            S = 83,
            UP = 38;

      if (primary && !active && key === S && !["input", "textarea"].includes(event.target.tagName.toLowerCase()) && !event.target.className.includes("ql-editor")) {
        event.preventDefault();
        this.onToggle.bind(this)();
      }
      else if (active && key === ESC && event.target === this.input) {
        event.preventDefault();
        this.onToggle.bind(this)();
      }
      else if (active && event.target === this.input) {

function keypress() {
        if (d3_event.keyCode === utilKeybinding.keyCodes.enter) {
            popover.selectAll('.list .list-item.focused button.choose')
                .each(function(d) { d.choose.call(this); });
            d3_event.preventDefault();
            d3_event.stopPropagation();
        }
    }

function keydown() {
        if (_altDisables && d3_event.keyCode === utilKeybinding.modifierCodes.alt) {
            _selection.selectAll('.hover')
                .classed('hover-suppressed', true)
                .classed('hover', false);

            _selection
                .classed('hover-disabled', true);

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

function keydown() {
        if (d3_event.keyCode === d3_keybinding.modifierCodes.alt) {
            if (context.surface().classed('nope')) {
                context.surface()
                    .classed('nope-suppressed', true);
            }
            context.surface()
                .classed('nope', false)
                .classed('nope-disabled', true);
        }
    }