Function handleTab

src/Offcanvas.js:180–205

(e)

  }

  handleTab(e) {
    if (e.which !== 9) return;
    if (this.offcanvasIndex < Offcanvas.openCount - 1) return; // last opened offcanvas

    const focusableChildren = this.getFocusableChildren();
    const totalFocusable = focusableChildren.length;
    if (totalFocusable === 0) return;
    const currentFocus = this.getFocusedChild();

    let focusedIndex = 0;

    for (let i = 0; i < totalFocusable; i += 1) {
      if (focusableChildren[i] === currentFocus) {
        focusedIndex = i;
        break;
      }
    }

    if (e.shiftKey && focusedIndex === 0) {
      e.preventDefault();
      focusableChildren[totalFocusable - 1].focus();
    } else if (!e.shiftKey && focusedIndex === totalFocusable - 1) {
      e.preventDefault();
      focusableChildren[0].focus();
    }
  }

  handleBackdropMouseDown(e) {
    this._mouseDownElement = e.target;