在dojo中有一个模块有hitch（）函数，它是专门为您的情况：
首先导入"dojo/_base/lang"，然后使用lang.hitch（）函数指出执行的上下文（引用您的模块）

require([.., "dojo/_base/lang", ...], function(.., lang, ...){
  
  //...

  _webCall: function(url){
    console.log(url)
  },
  
   
  onOpen: function(){
      var fireFunct =
      lang.hitch( this ,(function(){ // <--- execute function in the context of the module , this will point to the module not IFII function context
            var url = 'someurl';
            var executed = false;
            return returnFunc(){
               if(!executed){
                  executed = true;
                  this._webCall(url);
               }
            }
         })()
      );
      fireFunct();
  },

});

下面是不使用hitch而使用bind的方法

onOpen: function(){
        const webCallFnc = this._webCall.bind(this);
        const fireFunct = (() => {
            const url = 'someurl';
            let executed = false;
            return () => {
                if(!executed){
                    executed = true;
                    webCallFnc(url);
                }
            }
        })();
        fireFunct();
    },