7-7.js const twoArray = ["One", "Two"]; const threeArray = Object.assign([...twoArray], {2:"Three"}); console,log(threeArray); //returns (3) ["One", "Two", "Three"] Listing 7-7Returning a Copy of an Array So Data Is Not Mutated 在本例中,第一行创建了一个数组。第二...
The benefit here is that you see that the return is a string without having to guess. Type inference is a major help when it comes to working with other libraries that developers reference in their code, such as JQuery or even the Document Object Model (DOM). The other way to take adva...
};vardecaf =function(){this.name='decaf';this.basePrice=6; };// create object literals for the different sizesvarsmall = {getPrice:function(){returnthis.basePrice+2},getLabel:function(){returnthis.name+' small'} };varmedium = {getPrice:function(){returnthis.basePrice+4},getLabel:functi...
// 通过方法获取的元素是对象数据类型的值 console.log(typeof box); //=>"object" // console.log(box); // =>基于.dir可以看到一个对象的详细信息 /* id:操作元素的ID值 * className:操作(即获取和设置)元素的class样式类的值 * innerHTML:操作的元素的内容(可以识别标签) * innerText:和innerHTML的...
“Missing name in function declaration.”:“在中缺少名称”, “Expected an identifier and instead saw ‘{a}’.”:“需要有一个标识符,而不是’{a}’”, “Inner functions should be listed at the top of the outer function.”:“内部函数的声明应该放在此函数的顶部。”, ...
To instantiate a Generator object, one must use the function * declaration. Generators are functions that can be exited and later re-entered with its context (variable bindings) saved across re-entrances.For example, the downToOne function above can be rewritten as:...
代码语言:javascript 复制 varname="The Window";varobject={name:"My Object",getNameFunc:function(){returnfunction(){returnthis.name;};}};alert(object.getNameFunc()()); 代码片段二: 代码语言:javascript 复制 varname="The Window";varobject={name...
typeof Operator: The typeof operator is used to check the data type of a variable. While it's generally reliable, there are certain quirks, like how typeof null returns "object" instead of "null", due to a long-standing behavior in JavaScript's implementation....
You can get around this by declaring the properties during object creation: JavaScript varobj = {"a":10,"b":"hello world"} obj.// IntelliSense shows properties a and b You can also add a JSDoc comment as follows: JavaScript /** * @type {{a: number, b: string}} ...
We could access a property of an object using either of two ways: bracket notation or dot notation. In the former i.e bracket notation, we write the name of the property as a string within a pair of brackets ([]) following the object value. In the latter, we write the name of the...