错误捕获总结

参考 :

www.5kuai2.com/it/20221217…

blog.csdn.net/liubangbo/a…
blog.csdn.net/qq_43497320…

// try catch 可以捕获同步错误
function run() {
	try {
		console.log(a)
	} catch (err) {
		console.log('try catch 捕获同步错误:', err)
	}

}
run();

// try catch 捕获无法异步错误
function run1() {
	try {
		setTimeout(() => {
			console.log(b)
		}, 50)
	} catch (err) {
		console.log(' try catch 捕获异步错误:', err)
	}

}
run1();

// try catch 不能捕获promise错误,promise错误由内部catch捕获
function getHttpData() {
	return new Promise((resolve, reject) => {
		let obj = {
			status: 200,
		};
		if (obj.abc.status === 200) {
			resolve(200);
		} else {
			reject(404);
		}
	});
}

function test() {
	try {
		getHttpData()
			.then((res) => {
				console.log("liubbc res: ", res);
			})
			.catch((err) => {
				console.log("liubbc err: ", err);
			});
	} catch (error) {
		console.log(error, '无法捕获内部错误')
	}
}
test()

// 捕获异步错误: 用对异步代码加try  catch
function getHttpData1() {
	return new Promise((resolve, reject) => {
		setTimeout(() => {
			try {
				let obj = {
					status: 200,
				};
				if (obj.abc.status === 200) {
					resolve(200);
				} else {
					reject(404);
				}
			} catch (error) {
				reject(error)
			}
		}, 50)
	});
}

function test1() {
	getHttpData1()
		.then((res) => {
			console.log("liubbc res: ", res);
		})
		.catch((err) => {
			console.log("liubbc err: ", err);
		});
}
test1()

// 无法捕获异步错误： 使用async await
function getHttpData2() {
	return new Promise((resolve, reject) => {
		setTimeout(() => {
			try {
				let obj = {
					status: 200,
				};
				if (obj.abc.status === 200) {
					resolve(200);
				} else {
					reject(404);
				}
			} catch (error) {
				reject(error)
			}
		}, 50)
	});
}

async function test2() {
	try {
		const res = await getHttpData2();
		console.log(res, 'res')
	} catch (error) {
		console.log(error, 'error')
	}

}
test2()

结论:

• try catch只能捕获同步错误;
• 针对promise,错误由promise catch块捕获;
• 对于异步错误,可以由try catch包裹,reject到外层捕获