feat(layer): 新增 btnAsync 选项 (#2002)

* feat(layer): 新增 btnAsync 选项

* docs(layer): 添加 btnAsync 文档

* docs(layer): 添加 btnAsync 示例

* refactor: 删除按钮回调中的 loading 参数

* feat(layer): beforeEnd 回调新增第三个参数

* docs(layer): 更新文档

* docs: 优化 btnAsync 选项文档细节

* chore: 优化细节及增加注释

---------

Co-authored-by: 贤心 <3277200+sentsim@users.noreply.github.com>

docs/layer/detail/demo.md

@@ -88,6 +88,12 @@
   </textarea>
 </pre>
 
+<pre class="layui-code" lay-options="{preview: true, text: {preview: '异步按钮'}, codeStyle: 'height: 535px;', layout: ['preview', 'code'], tools: ['full']}">
+  <textarea>
+{{- d.include("/layer/examples/btnasync.md") }}
+  </textarea>
+</pre>
+
 
 <h3 id="demo-skin" lay-toc="{level: 2, hot: true}">主题风格</h3>
 

docs/layer/detail/options.md

@@ -397,6 +397,53 @@ layer.open({
     <tr>
 <td>
 
+[btnAsync](#options.btnAsync) <sup>2.9.12+</sup>
+
+</td>
+<td>
+  
+<div id="options.btnAsync" lay-pid="options" class="ws-anchor">
+
+异步按钮。开启之后，除 `layer.prompt` 的按钮外，按钮回调的返回值将支持 `boolean | Promise<boolean> | JQueryDeferred<boolean>` 类型，返回 `false` 或 `Promise.reject` 时阻止关闭。
+
+注意，此时 `yes` 和 `btn1`(两者等效) 回调的默认行为发生了变化，即由触发时不关闭弹层变为关闭弹层。
+
+</div>
+
+```
+var sleep = function (time) {
+  return $.Deferred(function (defer) {
+    setTimeout(function () {
+      defer.resolve();
+    }, time)
+  })
+}
+// 下面以 confirm 层为例
+layer.confirm('一个询问框的示例？', {
+    btnAsync: true,
+    btn: ['确定', '关闭'] // 按钮
+  }, 
+  function (index, layero, that) {
+    var defer = $.Deferred();
+    // 注: that.loading() 仅 btnAsync 开启后支持，参数为 boolean 类型，表示打开或关闭按钮的加载效果。
+    that.loading(true);
+    sleep(1000).then(defer.resolve);
+    return defer.promise();
+  }
+);
+```
+
+</td>
+<td>boolean</td>
+<td>
+
+`false`
+
+</td>
+    </tr>
+    <tr>
+<td>
+
 [skin](#options.skin)
 
 </td>
@@ -746,7 +793,7 @@ layer.open({
 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){
+  beforeEnd: function(layero, index, that){
     return $.Deferred(function(defer){
       var el = layero.find('#id');
       var val = el.val().trim();
@@ -914,4 +961,4 @@ layer.open({
 </td>
     </tr>
   </tbody>
-</table>
+</table>

docs/layer/examples/btnasync.md

@@ -0,0 +1,90 @@
+<button type="button" class="layui-btn layui-btn-primary" lay-on="bs_alert">alert</button>
+<button type="button" class="layui-btn layui-btn-primary" lay-on="bs_confirm">confirm</button>
+<button type="button" class="layui-btn layui-btn-primary" lay-on="bs_msg">msg</button>
+<button type="button" class="layui-btn layui-btn-primary" lay-on="bs_open">open</button>
+<button type="button" class="layui-btn layui-btn-primary" lay-on="bs_prompt">prompt(不支持)</button>
+
+<!-- import layui -->
+<script>
+layui.use(function () {
+  var $ = layui.$
+  var util = layui.util;
+  var sleep = function (time) {
+    return $.Deferred(function (defer) {
+      setTimeout(function () {
+        defer.resolve();
+      }, time)
+    })
+  }
+  var enableBtnAsync = true;
+
+  util.on({
+    bs_alert: function () {
+      layer.alert('对话框内容', {
+        btnAsync: enableBtnAsync,
+      }, function (index, layero, that) {
+        var defer = $.Deferred();
+        that.loading(true);
+        sleep(1000).then(defer.resolve);
+        return defer.promise();
+      });
+    },
+    bs_confirm: function () {
+      layer.confirm('一个询问框的示例？', {
+        btnAsync: enableBtnAsync,
+        btn: ['确定', '关闭'] //按钮
+      }, function (index, layero, that) {
+        var defer = $.Deferred();
+        that.loading(true);
+        sleep(1000).then(defer.resolve);
+        return defer.promise();
+      });
+    },
+    bs_msg: function () {
+      layer.msg('第二个回调', {
+        btnAsync: enableBtnAsync,
+        time: 20000, // 20s 后自动关闭
+        btn: ['明白了', '知道了'],
+        btn1: function (index, layero, that) {
+          var defer = $.Deferred();
+          that.loading(true);
+          sleep(1000).then(defer.resolve);
+          return defer.promise();
+        }
+      });
+    },
+    bs_open: function () {
+      layer.open({
+        btnAsync: enableBtnAsync,
+        type: 1,
+        area: ['500px', '300px'],
+        btn: ['确定', '关闭'],
+        btn1: function (index, layero, that) {
+          var defer = $.Deferred();
+          that.loading(true);
+          sleep(1000).then(defer.resolve);
+          return defer.promise();
+        },
+        btn2: function (index, layero, that) {
+          var defer = $.Deferred();
+          that.loading(true);
+          sleep(1000).then(defer.resolve);
+          return defer.promise();
+        }
+      })
+    },
+    // 不支持 btnAsync
+    bs_prompt: function () {
+      layer.prompt({
+        formType: 2,
+        value: '初始值',
+        title: '请输入值',
+        area: ['500px', '300px'] // 自定义文本域宽高
+      }, function (value, index, elem) {
+        alert(value);
+        layer.close(index);
+      });
+    }
+  })
+}); 
+</script>