We study the type decomposition and the rectangular $\text{AFD}$ property for ${{W}^{*}}-\text{TRO }\!\!'\!\!\text{ s}$. Like von Neumann algebras, every ${{W}^{*}}-\text{TRO}$ can be uniquely decomposed into the direct sum of ${{W}^{*}}-\text{TRO }\!\!'\!\!\text{ s}$ of $\text{type}\,I,\,\text{type}\,II$, and $\text{type}\,III$. We may further consider ${{W}^{*}}-\text{TRO }\!\!'\!\!\text{ s}$ of $\text{type}\,{{I}_{m,n}}$ with cardinal numbers $m$ and $n$, and consider ${{W}^{*}}-\text{TRO }\!\!'\!\!\text{ s}$ of $type\,I{{I}_{\lambda ,\mu }}\,\text{with}\,\lambda ,\,\mu \,=\,1\,\text{or}\,\infty $. It is shown that every separable stable ${{W}^{*}}-\text{TRO}$ (which includes $\text{type}\,{{I}_{\infty ,\infty }}$, $\text{type}\,I{{I}_{\infty ,\infty }}$ and $\text{type}\,III$) is $\text{TRO}$-isomorphic to a von Neumann algebra. We also introduce the rectangular version of the approximately finite dimensional property for ${{W}^{*}}-\text{TRO }\!\!'\!\!\text{ s}$. One of our major results is to show that a separable ${{W}^{*}}-\text{TRO}$ is injective if and only if it is rectangularly approximately finite dimensional. As a consequence of this result, we show that a dual operator space is injective if and only if its operator predual is a rigid rectangular $\mathcal{O}{{\mathcal{L}}_{1,{{1}^{+}}}}$ space (equivalently, a rectangular $\mathcal{O}{{\mathcal{L}}_{1,{{1}^{+}}}}$ space).