无涯教程-Javascript - every()函数 JavaScript every 数组中的所有元素都满足条件。

JavaScript every 数组中的所有元素都满足条件。

every() - 语法

array.every(callback[, thisObject]);

callback - 回调函数。
thisObject - 要在执行回调时用作的对象。

every() - 返回值

如果此数组中的每个元素都满足条件，则返回true。

every() - 相容性

此方法是ECMA-262标准的JavaScript扩展；因此，它可能不存在于该标准的其他实现中。要使其工作，您需要在脚本顶部添加以下代码。

if (!Array.prototype.every) {
   Array.prototype.every=function(fun /*, thisp*/) {
      var len=this.length;
      if (typeof fun != "function")
      throw new TypeError();
  </span><span class="kwd">var</span><span class="pln"> thisp</span><span class="pun">=</span><span class="pln">arguments</span><span class="pun">[</span><span class="lit">1</span><span class="pun">];</span><span class="pln">
  </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">var</span><span class="pln"> i</span><span class="pun">=</span><span class="lit">0</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&lt;</span><span class="pln"> len</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
     </span><span class="kwd">if</span><span class="pln"> </span><span class="pun">(</span><span class="pln">i </span><span class="kwd">in</span><span class="pln"> </span><span class="kwd">this</span><span class="pln"> </span><span class="pun">&amp;&amp;</span><span class="pln"> </span><span class="pun">!</span><span class="pln">fun</span><span class="pun">.</span><span class="pln">call</span><span class="pun">(</span><span class="pln">thisp</span><span class="pun">,</span><span class="pln"> </span><span class="kwd">this</span><span class="pun">[</span><span class="pln">i</span><span class="pun">],</span><span class="pln"> i</span><span class="pun">,</span><span class="pln"> </span><span class="kwd">this</span><span class="pun">))</span><span class="pln">
     </span><span class="kwd">return</span><span class="pln"> </span><span class="kwd">false</span><span class="pun">;</span><span class="pln">
  </span><span class="pun">}</span><span class="pln">
  </span><span class="kwd">return</span><span class="pln"> </span><span class="kwd">true</span><span class="pun">;</span><span class="pln">

};
}

every() - 示例

<html>
   <head>
      <title>JavaScript Array every Method</title>
   </head>
   
   <body>   
      <script type="text/javascript">
         if (!Array.prototype.every) {
            Array.prototype.every=function(fun /*, thisp*/) {
               var len=this.length;
               if (typeof fun != "function")
               throw new TypeError();
               
               var thisp=arguments[1];
               for (var i=0; i < len; i++) {
                  if (i in this && !fun.call(thisp, this[i], i, this))
                  return false;
               }
               return true;
            };
         }
         function isBigEnough(element, index, array) {
            return (element >= 10);
         }
         var passed=[12, 5, 8, 130, 44].every(isBigEnough);
         document.write("First Test Value : " + passed ); 
         
         passed=[12, 54, 18, 130, 44].every(isBigEnough);
         document.write("Second Test Value : " + passed ); 
      </script>      
   </body>
</html>

运行上面代码输出

First Test Value : falseSecond Test Value : true

无涯教程-Javascript - every()函数

every() - 语法

every() - 返回值

every() - 相容性

every() - 示例

参考链接