typescript数组 TypeScript 数字

类似JavaScript的TypeScript支持数字值为Number对象。number对象将数字文本转换为number类的实例。number类作为一个包装器，并允许对数字文本进行操作，因为它们是对象。

语法

var var_name = new Number(value)

如果一个非数字的参数作为参数传递给Number的构造函数，则返回NaN（非数字）

下表列出了一组Number对象的属性 -

示例

console.log("TypeScript Number Properties: "); 
console.log("Maximum value that a number variable can hold: " + Number.MAX_VALUE); 
console.log("The least value that a number variable can hold: " + Number.MIN_VALUE); 
console.log("Value of Negative Infinity: " + Number.NEGATIVE_INFINITY); 
console.log("Value of Negative Infinity:" + Number.POSITIVE_INFINITY);

在编译时，它将在JavaScript中生成相同的代码。

它的输出如下：

TypeScript Number Properties:  
Maximum value that a number variable can hold: 1.7976931348623157e+308 
The least value that a number variable can hold: 5e-324 
Value of Negative Infinity: -Infinity 
Value of Negative Infinity:Infinity

示例：NaN

var month = 0 
if( month<=0 || month >12) { 
   month = Number.NaN 
   console.log("Month is "+ month) 
} else { 
   console.log("Value Accepted..") 
}

在编译时，它会在JavaScript中产生相同的代码。

它的输出如下：

Month is NaN

示例：prototype

function employee(id:number,name:string) { 
   this.id = id 
   this.name = name 
} 

var emp = new employee(123,"Smith") 
employee.prototype.email = "smith@abc.com" 

console.log("Employee 's Id: "+emp.id) 
console.log("Employee's name: "+emp.name) 
console.log("Employee's Email ID: "+emp.email)

在编译时，它会生成以下JavaScript代码：

//Generated by typescript 1.8.10
function employee(id, name) {
   this.id = id;
   this.name = name;
}

var emp = new employee(123, "Smith");
employee.prototype.email = "smith@abc.com";

console.log("Employee 's Id: " + emp.id);
console.log("Employee's name: " + emp.name);
console.log("Employee's Email ID: " + emp.email);

它的输出如下：

Employee’s Id: 123 
Emaployee’s name: Smith 
Employee’s Email ID: smith@abc.com

number方法

Number对象仅包含作为每个对象定义一部分的默认方法。下面列出了一些常用方法：