TypeScript 数字

TypeScript和JavaScript一样支持将数值作为Number对象。一个Number对象将数值文字转换为Number类的实例。Number类充当了一个包装器，可以将数值文字作为对象来操作。

语法

var var_name = new Number(value)

在将一个非数值参数作为构造函数的参数传递时，它会返回 NaN（非数值）。

以下表格列出了 Number 对象的一些属性 −

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);

编译后，它将生成相同的JavaScript代码。

其输出如下：

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..") 
}

编译后，它将在JavaScript中生成相同的代码。

输出结果如下：

Month is NaN

示例：原型

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)

编译后将生成以下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 对象仅包含每个对象定义中默认的方法。以下是一些常用的方法：