const filterData: FilterData = {
      filter: this.categorySlug ?
        { "category.slug": this.categorySlug } : null,
      pagination: null,
      select: mSelect,
      sort: { createdAt: -1 },
    };

<button (click)="handleClick('teaching')">Teacher</button>

  handleClick(data: any) {
    this.filter = {
      "category.slug": data,
    }
    this.getAllBlog();
  }

    const filter: FilterData = {
      // filter: this.filter,
      filter: { ...this.filter, quantity: { $lte: Number(10) } },
      pagination: null,
      select: mSelect,
      sort: this.sortQuery,
    };