# ES6 解構賦值 解構賦值是對賦值運算符的擴展。 他是一種針對數組或者對象進行模式匹配，然后對其中的變量進行賦值。 在代碼書寫上簡潔且易讀，語義更加清晰明了；也方便了復雜對象中數據字段獲取。 ``` <pre class="calibre13">``` <span class="token2">let</span> <span class="token1">[</span>a<span class="token1">,</span> b<span class="token1">,</span> c<span class="token1">]</span> <span class="token">=</span> <span class="token1">[</span><span class="token5">1</span><span class="token1">,</span> <span class="token5">2</span><span class="token1">,</span> <span class="token5">3</span>\<span class="token1">]</span><span class="token1">;</span> <span class="token6">// a = 1 </span> <span class="token6">// b = 2 </span> <span class="token6">// c = 3</span> <span class="token2">let</span> <span class="token1">[</span>a<span class="token1">,</span> b<span class="token1">,</span> c<span class="token1">,</span> d<span class="token1">,</span> e<span class="token1">]</span> <span class="token">=</span> <span class="token4">'hello'</span><span class="token1">;</span> <span class="token6">// a = 'h' </span> <span class="token6">// b = 'e'</span> <span class="token6">// c = 'l' </span> <span class="token6">// d = 'l' </span> <span class="token6">// e = 'o'</span> ``` ``` 當解構模式有匹配結果，且匹配結果是 undefined 時，會觸發默認值作為返回結果。 ``` <pre class="calibre14">``` <span class="token2">let</span> <span class="token1">[</span>a <span class="token">=</span> <span class="token5">2</span><span class="token1">]</span> <span class="token">=</span> <span class="token1">[</span>undefined<span class="token1">]</span><span class="token1">;</span> <span class="token6">// a = 2</span> ``` ```