feat(layer): 新增 beforeEnd 回调 (#1968)

* feat(layer): 新增 beforeEnd 回调

* docs(layer): 更新 beforeEnd 文档

* update

* update

* refactor: 简化代码

* docs(layer): 更新 beforeEnd 文档

* update

* update

docs/layer/detail/options.md

@@ -733,6 +733,41 @@ layer.open({
     <tr>
 <td>
 
+[beforeEnd](#options.beforeEnd) <sup>2.9.11+</sup>
+
+</td>
+<td colspan="3">
+  
+<div id="options.beforeEnd" lay-pid="options" class="ws-anchor">
+弹层被关闭前的回调函数。如果返回 false 或者 Promise.reject，将会取消关闭操作。
+</div>
+
+```
+layer.open({
+  content: '<div style="padding: 32px;"><input id="id"/></div>',
+  /** @type {(layero: JQuery, index: number) => boolean | JQueryDeferred<boolean> | Promise<boolean>} */
+  beforeEnd: function(layero, index){
+    return $.Deferred(function(defer){
+      var el = layero.find('#id');
+      var val = el.val().trim();
+      if(val){
+        layer.confirm('关闭后您填写的内容将不会得到保存，确定关闭吗？', function (i) {
+          layer.close(i);
+          defer.resolve(true)
+        });
+      }else{
+        defer.resolve(true)
+      }
+    }).promise();
+  }
+});  
+```
+
+</td>
+    </tr>
+    <tr>
+<td>
+
 [end](#options.end)
 
 </td>

src/modules/layer.js

@@ -30,6 +30,7 @@ var ready = {
     removeFocus: true
   }, 
   end: {}, 
+  beforeEnd: {},
   events: {resize: {}}, 
   minStackIndex: 0,
   minStackArr: [],
@@ -925,6 +926,7 @@ Class.pt.callback = function(){
   });
 
   config.end && (ready.end[that.index] = config.end);
+  config.beforeEnd && (ready.beforeEnd[that.index] = config.beforeEnd);
 };
 
 // for ie6 恢复 select
@@ -1219,6 +1221,7 @@ layer.close = function(index, callback){
 
   if(!layero[0]) return;
 
+  var executor = function(){
     // 关闭动画
     var closeAnim = ({
       slideDown: 'layer-anim-slide-down-out',
@@ -1301,6 +1304,34 @@ layer.close = function(index, callback){
         remove();
       }, 200);
     }
+  }
+
+  if(!hideOnClose && typeof ready.beforeEnd[index] === 'function'){
+    // 类似 Promise.resolve
+    var promiseLikeResolve = function(value){
+      var deferred = $.Deferred();
+
+      if(value && typeof value.then === 'function'){
+        value.then(deferred.resolve, deferred.reject);
+      }else{
+        deferred.resolve(value);
+      }
+      return deferred.promise();
+    }
+
+    promiseLikeResolve(ready.beforeEnd[index](layero, index))
+      .then(function(result){
+        if(result !== false){
+          delete ready.beforeEnd[index];
+          executor();
+        }
+      }, function(reason){
+        reason !== undefined && window.console && window.console.error('layer error hint: ' + reason);
+      });
+  }else{
+    delete ready.beforeEnd[index];
+    executor();
+  }
 };
 
 // 关闭所有层