discourse/app/assets/javascripts/select-kit/mixins/events.js.es6

export default Ember.Mixin.create({
  init() {
    this._super();

    this.keys = {
      TAB: 9,
      ENTER: 13,
      ESC: 27,
      UP: 38,
      DOWN: 40,
      BACKSPACE: 8,
      LEFT: 37,
      RIGHT: 39,
      A: 65
    };
  },

  willDestroyElement() {
    this._super();

    $(document).off("mousedown.select-kit");

    if (this.$header()) {
      this.$header()
        .off("blur.select-kit")
        .off("focus.select-kit")
        .off("keypress.select-kit")
        .off("keydown.select-kit");
    }

    if (this.$filterInput()) {
      this.$filterInput()
        .off("change.select-kit")
        .off("keydown.select-kit")
        .off("keypress.select-kit");
    }
  },

  didInsertElement() {
    this._super();

    $(document)
      .on("mousedown.select-kit", event => {
        if (!this.element || this.isDestroying || this.isDestroyed) {
          return true;
        }

        if (Ember.$.contains(this.element, event.target)) {
          event.stopPropagation();
          if (!this.get("renderedBodyOnce")) return;
          if (!this.get("isFocused")) return;
        } else {
          this.didClickOutside(event);
        }

        return true;
    });

    this.$header()
      .on("blur.select-kit", () => {
        if (!this.get("isExpanded") && this.get("isFocused")) {
          this.close();
        }
      })
      .on("focus.select-kit", (event) => {
        this.set("isFocused", true);
        this._destroyEvent(event);
      })
      .on("keydown.select-kit", (event) => {
        const keyCode = event.keyCode || event.which;

        if (document.activeElement !== this.$header()[0]) return event;

        if (keyCode === this.keys.TAB && event.shiftKey) { this.unfocus(event); }
        if (keyCode === this.keys.TAB && !event.shiftKey) this.tabFromHeader(event);
        if (Ember.isEmpty(this.get("filter")) && keyCode === this.keys.BACKSPACE) this.backspaceFromHeader(event);
        if (keyCode === this.keys.ESC) this.escapeFromHeader(event);
        if (keyCode === this.keys.ENTER) this.enterFromHeader(event);
        if ([this.keys.UP, this.keys.DOWN].includes(keyCode)) this.upAndDownFromHeader(event);
        if (Ember.isEmpty(this.get("filter")) &&
            [this.keys.LEFT, this.keys.RIGHT].includes(keyCode)) {
              this.leftAndRightFromHeader(event);
        }
        return event;
      })
      .on("keypress.select-kit", (event) => {
        const keyCode = event.keyCode || event.which;

        if (keyCode === this.keys.ENTER) return true;
        if (keyCode === this.keys.TAB) return true;

        this.expand(event);

        if (this.get("filterable") || this.get("autoFilterable")) {
          this.set("renderedFilterOnce", true);
        }

        if (keyCode >= 65 && keyCode <= 122) {
          Ember.run.schedule("afterRender", () => {
            this.$filterInput()
                .focus()
                .val(this.$filterInput().val() + String.fromCharCode(keyCode));
          });
        }

        return false;
      });

    this.$filterInput()
      .on("change.select-kit", (event) => {
        this.send("onFilterComputedContent", $(event.target).val());
      })
      .on("keypress.select-kit", (event) => {
        event.stopPropagation();
      })
      .on("keydown.select-kit", (event) => {
        const keyCode = event.keyCode || event.which;

        if (Ember.isEmpty(this.get("filter")) &&
            keyCode === this.keys.BACKSPACE &&
            typeof this.didPressBackspaceFromFilter === "function") {
          this.didPressBackspaceFromFilter(event);
        };

        if (keyCode === this.keys.TAB && event.shiftKey) { this.unfocus(event); }
        if (keyCode === this.keys.TAB && !event.shiftKey) this.tabFromFilter(event);
        if (keyCode === this.keys.ESC) this.escapeFromFilter(event);
        if (keyCode === this.keys.ENTER) this.enterFromFilter(event);
        if ([this.keys.UP, this.keys.DOWN].includes(keyCode)) this.upAndDownFromFilter(event);

        if (Ember.isEmpty(this.get("filter")) &&
            [this.keys.LEFT, this.keys.RIGHT].includes(keyCode)) {
          this.leftAndRightFromFilter(event);
        }
      });
  },

  didPressTab(event) {
    if (this.$highlightedRow().length && this.get("isExpanded")) {
      this.close(event);
      this.$header().focus();
      const guid = this.$highlightedRow().attr("data-guid");
      this.select(this._findComputedContentItemByGuid(guid));
      return true;
    }

    if (Ember.isEmpty(this.get("filter"))) {
      this.close(event);
      return true;
    }

    return true;
  },

  didPressEnter(event) {
    if (!this.get("isExpanded")) {
      this.expand(event);
    } else if (this.$highlightedRow().length) {
      this.close(event);
      this.$header().focus();
      const guid = this.$highlightedRow().attr("data-guid");
      this.select(this._findComputedContentItemByGuid(guid));
    }

    return true;
  },

  didClickSelectionItem(computedContentItem) {
    this.focus();
    this.deselect(computedContentItem);
  },

  didClickRow(computedContentItem) {
    this.close();
    this.focus();
    this.select(computedContentItem);
  },

  didPressEscape(event) {
    this._destroyEvent(event);

    if (this.get("highlightedSelection").length && this.get("isExpanded")) {
      this.clearHighlightSelection();
    } else {
      this.unfocus(event);
    }
  },

  didPressUpAndDownArrows(event) {
    this._destroyEvent(event);

    this.clearHighlightSelection();

    const keyCode = event.keyCode || event.which;

    if (!this.get("isExpanded")) {
      this.expand(event);

      if (this.$selectedRow().length === 1) {
        this._highlightRow(this.$selectedRow());
        return;
      }

      return;
    }

    const $rows = this.$rows();

    if (!$rows.length) { return; }

    if ($rows.length === 1) {
      this._rowSelection($rows, 0);
      return;
    }

    const direction = keyCode === 38 ? -1 : 1;

    Ember.run.throttle(this, this._moveHighlight, direction, $rows, 32);
  },

  didPressBackspaceFromFilter(event) { this.didPressBackspace(event); },
  didPressBackspace(event) {
    if (!this.get("isExpanded")) {
      this.expand();
      if (event) event.stopImmediatePropagation();
      return;
    }

    if (!this.get("selection").length) return;

    if (!Ember.isEmpty(this.get("filter"))) {
      this.clearHighlightSelection();
      return;
    }

    if (!this.get("highlightedSelection").length) {
      // try to highlight the last non locked item from the current selection
      Ember.makeArray(this.get("selection")).slice().reverse().some(selection => {
        if (!Ember.get(selection, "locked")) {
          this.highlightSelection(selection);
          return true;
        }
      });

      if (event) event.stopImmediatePropagation();
    } else {
      this.deselect(this.get("highlightedSelection"));
      if (event) event.stopImmediatePropagation();
    }
  },

  didPressSelectAll() {
    this.highlightSelection(Ember.makeArray(this.get("selection")));
  },

  didClickOutside(event) {
    if (this.get("isExpanded") && $(event.target).parents(".select-kit").length) {
      this.close(event);
      return false;
    }

    this.close(event);
    return;
  },

  // make sure we don’t propagate a click outside component
  // to avoid closing a modal containing the component for example
  click(event) {
    this._destroyEvent(event);
  },

  didPressLeftAndRightArrows(event) {
    if (!this.get("isExpanded")) {
      this.expand();
      event.stopImmediatePropagation();
      return;
    }

    if (Ember.isEmpty(this.get("selection"))) return;

    const keyCode = event.keyCode || event.which;

    if (keyCode === this.keys.LEFT) {
      const prev = this.get("highlightedSelection.lastObject");
      const indexOfPrev = this.get("selection").indexOf(prev);

      if (this.get("selection")[indexOfPrev - 1]) {
        this.highlightSelection(this.get("selection")[indexOfPrev - 1]);
      } else {
        this.highlightSelection(this.get("selection.lastObject"));
      }
    } else {
      const prev = this.get("highlightedSelection.firstObject");
      const indexOfNext= this.get("selection").indexOf(prev);

      if (this.get("selection")[indexOfNext + 1]) {
        this.highlightSelection(this.get("selection")[indexOfNext + 1]);
      } else {
        this.highlightSelection(this.get("selection.firstObject"));
      }
    }
  },

  tabFromHeader(event) { this.didPressTab(event); },
  tabFromFilter(event) { this.didPressTab(event); },

  escapeFromHeader(event) { this.didPressEscape(event); },
  escapeFromFilter(event) { this.didPressEscape(event); },

  upAndDownFromHeader(event) { this.didPressUpAndDownArrows(event); },
  upAndDownFromFilter(event) { this.didPressUpAndDownArrows(event); },

  leftAndRightFromHeader(event) { this.didPressLeftAndRightArrows(event); },
  leftAndRightFromFilter(event) { this.didPressLeftAndRightArrows(event); },

  backspaceFromHeader(event) { this.didPressBackspace(event); },

  enterFromHeader(event) { this.didPressEnter(event); },
  enterFromFilter(event) { this.didPressEnter(event); },

  _moveHighlight(direction, $rows) {
    const currentIndex = $rows.index(this.$highlightedRow());
    let nextIndex = currentIndex + direction;

    if (nextIndex < 0) {
      nextIndex = $rows.length - 1;
    } else if (nextIndex >= $rows.length) {
      nextIndex = 0;
    }

    this._rowSelection($rows, nextIndex);
  },

  _rowSelection($rows, nextIndex) {
    const highlightableValue = $rows.eq(nextIndex).attr("data-value");
    const $highlightableRow = this.$findRowByValue(highlightableValue);
    this._highlightRow($highlightableRow);
  },

  _highlightRow($row) {
    Ember.run.schedule("afterRender", () => {
      $row.trigger("mouseover").focus();
      this.focus();
    });
  }
});