TypeScript 數(shù)字

類似JavaScript的TypeScript支持?jǐn)?shù)字值為Number對象。number對象將數(shù)字文本轉(zhuǎn)換為number類的實例。number類作為一個包裝器，并允許對數(shù)字文本進(jìn)行操作，因為它們是對象。

語法

var var_name = new Number(value)

如果一個非數(shù)字的參數(shù)作為參數(shù)傳遞給Number的構(gòu)造函數(shù)，則返回NaN（非數(shù)字）

下表列出了一組Number對象的屬性 -

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);

在編譯時，它將在JavaScript中生成相同的代碼。

它的輸出如下：

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..") 
}

在編譯時，它會在JavaScript中產(chǎn)生相同的代碼。

它的輸出如下：

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)

在編譯時，它會生成以下JavaScript代碼：

//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);

它的輸出如下：

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

number方法

Number對象僅包含作為每個對象定義一部分的默認(rèn)方法。下面列出了一些常用方法：