Function trapFocus

src/Offcanvas.js:268–301

(ev)

  }

  trapFocus(ev) {
    if (!this.props.trapFocus) {
      return;
    }

    if (!this._element) {
      // element is not attached
      return;
    }

    if (this._dialog.current === ev.target) {
      // initial focus when the Offcanvas is opened
      return;
    }

    if (this.offcanvasIndex < Offcanvas.openCount - 1) {
      // last opened offcanvas
      return;
    }

    const children = this.getFocusableChildren();

    for (let i = 0; i < children.length; i += 1) {
      // focus is already inside the Offcanvas
      if (children[i] === ev.target) return;
    }

    if (children.length > 0) {
      // otherwise focus the first focusable element in the Offcanvas
      ev.preventDefault();
      ev.stopPropagation();
      children[0].focus();
    }
  }

  init() {
    try {