JS版本(闭包)
实现函数(方法)
function TypeAndSizeVerification(accept = '.jpg, .jpeg, .png, .gif', setFileSize = 10) {
if (typeof accept !== 'string') throw new Error(`${
typeof accept} is not the expected type, but the string type is expected.`);
if (typeof setFileSize !== 'number') throw new Error(`${
typeof accept} is not the expected type, but the string type is expected.`);
// 去除所有空格的正则表达式
let reg = /[\t\r\f\n\s]*/g,
// 文件后缀名
targetArray = undefined;
targetArray = accept.split(reg);
targetArray = targetArray.join('');
targetArray = targetArray.split(',');
// 去除点，并且转为小写
targetArray = targetArray.map(item => {
item = item.substring(1);
item = item.toLowerCase();
return item;
});
return function (fileType = '', fileSize = 0) {
if (typeof fileType !== 'string') throw new Error(`${
typeof fileType} is not the expected type, but the string type is expected.`);
if (typeof fileSize !== 'number') throw `${
typeof fileSize} is not the expected type, but the number type is expected.`;
if (fileType.lastIndexOf(".") !== -1) {
fileType = fileType.substring(fileType.lastIndexOf(".") + 1);
} else if (fileType.lastIndexOf("/") !== -1) {
fileType = fileType.split('/');
fileType = fileType[1];
} else {
throw `'${
fileType}' not the correct file type.`;
}
fileType = fileType.toLowerCase();
// 检测文件类型
let isFileType = targetArray.includes(fileType),
// 文件大小为20M
isFileSize = fileSize / 1024 / 1024 < setFileSize;
return isFileType && isFileSize;
}
}
代码解析
关于正则表达式的书写方式
1、let reg = /[\t\r\f\n\s]*/g;
2、let reg = new RegExp("\[\\t\\r\\f\\n\\s\]*", "g");
3、let reg = new RegExp(/[\t\r\f\n\s]*/, "g");
代码简写方式
targetArray = accept.split(reg);
targetArray = targetArray.join('');
targetArray = targetArray.split(',');
以上三行代码可以简写为以下方式，只是个人习惯一步一步实现
targetArray = accept.split(reg).join("").split(",");
正确参数的方法执行示例
let TASV = new TypeAndSizeVerification('.jpg, .jpeg, .png, .GIF', 20);
console.log(TASV('guiling.jpg', 1873));
// true
console.log(TASV('lingyi.txt', 1024));
// false
console.log(TASV('image/png', 1024));
// true
console.log(TASV('image/jpeg', 86852398));
// false
console.log(TASV('guiling.JPG', 1024));
// true
console.log(TASV('lingyi.gif', 1024));
// true
错误参数的方法执行示例
let TASV = new TypeAndSizeVerification(908);
// Uncaught Error: number is not the expected type, but the string type is expected.
console.log(TASV([1, 2], 86852398));
// Uncaught Error: object is not the expected type, but the string type is expected.
console.log(TASV('image/jpg', '86852398'));
// Uncaught string is not the expected type, but the number type is expected.
console.log(TASV('guilinglingyi', 1024));
// Uncaught 'guilinglingyi' not the correct file type.
TS版本(构造类)
实现函数(方法)
export class TypeAndSizeVerification {
targetArray: any;
setFileSize: number;
constructor(accept: string = '.jpg, .jpeg, .png, .gif', setFileSize: number = 10) {
if (typeof accept !== 'string') throw new Error(`${
typeof accept} is not the expected type, but the string type is expected.`);
if (typeof setFileSize !== 'number') throw new Error(`${
typeof accept} is not the expected type, but the string type is expected.`);
this.targetArray = accept;
this.setFileSize = setFileSize;
this.handleType();
}
// 被private修饰的方法属于私有方法，只能在声明它的类内部访问，
// 无法从类的外部或子类中访问。
private handleType(): void {
// 去除所有空格的正则表达式
let reg: RegExp = /[\t\r\f\n\s]*/g;
this.targetArray = this.targetArray.split(reg);
this.targetArray = this.targetArray.join('');
this.targetArray = this.targetArray.split(',');
// 去除点，并且转为小写
this.targetArray = this.targetArray.map((item: string) => {
item = item.substring(1);
item = item.toLowerCase();
return item;
});
}
handleResult(fileType: any = '', fileSize: number = 0): boolean {
if (typeof fileType !== 'string') throw new Error(`${
typeof fileType} is not the expected type, but the string type is expected.`);
if (typeof fileSize !== 'number') throw `${
typeof fileSize} is not the expected type, but the number type is expected.`;
if (fileType.lastIndexOf(".") !== -1) {
fileType = fileType.substring(fileType.lastIndexOf(".") + 1);
} else if (fileType.lastIndexOf("/") !== -1) {
fileType = fileType.split('/');
fileType = fileType[1];
} else {
throw `'${
fileType}' not the correct file type.`;
}
fileType = fileType.toLowerCase();
// 检测文件类型
let isFileType: boolean = this.targetArray.includes(fileType),
// 文件大小为20M
isFileSize: boolean = fileSize / 1024 / 1024 < this.setFileSize;
return isFileType && isFileSize;
}
}
使用构造类
import {
TypeAndSizeVerification } from '@/utils/typeAndSizeVerification';
let accept = ref(".jpg, .jpeg, .png"),
TASV = new TypeAndSizeVerification(accept.value, 20);
// file.name
console.log(TASV.handleResult('test.txt'));
// file.type
console.log(TASV.handleResult('image/png'));
代码解析
private
被
private修饰的方法属于私有方法，只能在声明它的类内部访问，无法从类的外部或子类中访问。class MyClass { private privateMethod() { // 私有方法的实现 } public publicMethod() { // 公共方法可以调用私有方法 this.privateMethod(); } } const instance = new MyClass(); // 可以调用公共方法 instance.publicMethod(); // 无法调用私有方法，会导致编译错误 // instance.privateMethod();
protected
被
protected修饰的方法是受保护方法，只能在声明它的类及其子类内部访问，无法从类的外部访问。这使得方法对于类的继承体系中的子类是可见的。class MyBaseClass { protected protectedMethod() { // 受保护方法的实现 } } class MyDerivedClass extends MyBaseClass { public useProtectedMethod() { // 子类可以调用受保护方法 this.protectedMethod(); } } const baseInstance = new MyBaseClass(); // 无法调用受保护方法，会导致编译错误 // baseInstance.protectedMethod(); const derivedInstance = new MyDerivedClass(); // 可以调用使用受保护方法的公共方法 derivedInstance.useProtectedMethod();
throw和throw new Error()对比
throw new Error()抛出的异常更加直观优雅，不像throw抛出的异常那么杂糅。建议多使用throw new Error()。