node . js util . types . isboxedprimitive()方法
原文:https://www . geesforgeks . org/node-js-util-types-is box edprimitive-method/
util.types.isBoxedPrimitive()方法是 util 模块的内置应用编程接口，主要设计用于支持 Node.js 自身内部 API 的需求。
util.types.isBoxedPrimitive()方法用于检查给定值是否为装箱的图元。
语法:
util.types.isBoxedPrimitive( value )
参数:该函数接受一个参数，如上所述，如下所述:
- Value: It is the value of the packing element to be checked.
返回值:如果传递的值是装箱的图元，则返回布尔值，即真，否则返回假。
下面的例子说明了 Node.js 中的 util.types.isBoxedPrimitive()方法:
例 1:
// Node.js program to demonstrate the
// util.types.isBoxedPrimitive() method
// Import the util module
const util = require('util');
// Checking an unboxed string
let unboxedString = "GeeksforGeeks";
console.log("Value:", unboxedString);
isBoxed = util.types.isBoxedPrimitive(unboxedString);
console.log("Value is a boxed primitive:", isBoxed);
// Checking a boxed string
let boxedString = new String("GeeksforGeeks");
console.log("Value:", boxedString);
isBoxed = util.types.isBoxedPrimitive(boxedString);
console.log("Value is a boxed primitive:", isBoxed);
// Checking an unboxed integer
let unboxedInteger = 99;
console.log("Value:", unboxedInteger);
isBoxed = util.types.isBoxedPrimitive(unboxedInteger);
console.log("Value is a boxed primitive:", isBoxed);
// Checking a boxed integer
let boxedInt = new Number(99);
console.log("Value:", boxedInt);
isBoxed = util.types.isBoxedPrimitive(boxedInt);
console.log("Value is a boxed primitive:", isBoxed);
// Checking an unboxed boolean
let unboxedBool = false;
console.log("Value:", unboxedBool);
isBoxed = util.types.isBoxedPrimitive(unboxedBool);
console.log("Value is a boxed primitive:", isBoxed);
// Checking a boxed boolean
let boxedBool = new Boolean(false);
console.log("Value:", boxedBool);
isBoxed = util.types.isBoxedPrimitive(boxedBool);
console.log("Value is a boxed primitive:", isBoxed);
输出:
Value: GeeksforGeeks
Value is a boxed primitive: false
Value: [String: 'GeeksforGeeks']
Value is a boxed primitive: true
Value: 99
Value is a boxed primitive: false
Value: [Number: 99]
Value is a boxed primitive: true
Value: false
Value is a boxed primitive: false
Value: [Boolean: false]
Value is a boxed primitive: true
例 2:
// Node.js program to demonstrate the
// util.types.isBoxedPrimitive() method
// Import the util module
const util = require('util');
// Checking for the symbol primitive
let symbol = Symbol('geeks');
console.log("Value:", symbol);
isBoxed = util.types.isBoxedPrimitive(symbol);
console.log("Value is a boxed primitive:", isBoxed);
// Checking again after creating a symbol wrapper
let symbolObj = new Object(Symbol('geeks'));
console.log("Value:", symbolObj);
isBoxed = util.types.isBoxedPrimitive(symbolObj);
console.log("Value is a boxed primitive:", isBoxed);
Value: Symbol(geeks)
Value is a boxed primitive: false
Value: [Symbol: Symbol(geeks)]
Value is a boxed primitive: true
参考:https://nodejs . org/API/util . html # util _ util _ types _ isboxedprimitive _ value
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