Object.freeze 和Object.seal 在“实用性”方面存在不足,它们都只是对对象的第一层有效。 const obj = { author: "DevPoint", detail: { view: 100 } }; console.log(Object.getOwnPropertyDescriptors(obj.detail)); /* { view: { value: 100, writable: true, enumerable: true, configurable: true ...
浏览器兼容性 objObject.defineProperties(obj,{property1:{value:true,writable:true,},property2:{value:"Hello",writable:false,},// 等等……}); 规范 Specification ECMAScript® 2026 Language Specification #sec-object.defineproperties
Accepts an optional options object. Copy $('#myModal').modal({ keyboard: false }) .modal('toggle') Manually toggles a modal. Returns to the caller before the modal has actually been shown or hidden (i.e. before the shown.bs.modal or hidden.bs.modal event occurs). Copy $('#myModal...
functionfunc(a=55){a=99;// updating a does not also update arguments[0]console.log(arguments[0]);}func(10);// 10 并且 js functionfunc(a=55){console.log(arguments[0]);}func();// undefined 规范 Specification ECMAScript® 2026 Language Specification ...
?原始类型(Primitive type)原始类型又称基本类型,包括string、number、bigint、boolean、undefined、null和symbol(ES6 新增)。 原始类型的值被称为原始值(Primitive value)。 补充:虽然typeof null返回的是'object',但是null真的不是对象,会出现这样的结果其实是 JavaScript 的一个 Bug~ ...
view). We call this variable the “view model” after a famous and useful technique for implementing UIs called Model-View-ViewModel (MVVM). Once we’ve built our view model as a bindable object, as the underlying properties change (the person, in our case) the view is updated. We then...
Throws an error on invalid use ofdelete.Thedeleteoperator (used to remove properties from objects) cannot be used on nonconfigurable properties of the object. Nonstrict code will fail silently when an attempt is made to delete a nonconfigurable property, whereas strict mode will throw an error ...
When true, all the properties of the object can be accessed. Default Value:false maxScale Property maxScale Number The maximum scale (most zoomed in) at which the layer is visible in the view. If the map is zoomed in beyond this scale, the layer will not be visible. A value of ...
ObjectSymbol3DLayer is used to render Point geometries using a volumetric 3D shape (e.g., a sphere or cylinder) with a PointSymbol3D in a SceneView. MapView does not support 3D symbols. Polygon features may also be rendered with ObjectSymbol3DLayers, but the object symbol layer must be ...
然后使用 load(clientObject) 函数获取代表这些项的列表项对象。 从列表检索项 可以使用 getItems(query) 函数定义协作应用程序标记语言 (CAML) 查询,以指定要返回哪些项。 您可以传递一个未定义的 CamlQuery 对象以返回列表中的所有项,也可以使用 set_viewXml 函数定义一个 CAML 查询并返回符合特定条件的项。