Error Propagation in JavaScript

1// Method 1: Re-throw error
2function level1() {
3    try {
4        level2();
5    } catch (error) {
6        console.error('Level 1 caught:', error.message);
7        throw error; // Re-throw
8    }
9}
10
11function level2() {
12    try {
13        level3();
14    } catch (error) {
15        console.error('Level 2 caught:', error.message);
16        throw error; // Re-throw
17    }
18}
19
20function level3() {
21    throw new Error('Error from level 3');
22}
23
24try {
25    level1();
26} catch (error) {
27    console.error('Final catch:', error.message);
28}
29
30// Method 2: Wrap error
31function processData(data) {
32    try {
33        return JSON.parse(data);
34    } catch (error) {
35        throw new Error(`Failed to process data: ${error.message}`);
36    }
37}
38
39try {
40    processData('invalid');
41} catch (error) {
42    console.error('Wrapped error:', error.message);
43}
44
45// Method 3: Error chain
46class ChainedError extends Error {
47    constructor(message, cause) {
48        super(message);
49        this.cause = cause;
50        this.name = 'ChainedError';
51    }
52}
53
54function operation1() {
55    try {
56        operation2();
57    } catch (error) {
58        throw new ChainedError('Operation 1 failed', error);
59    }
60}
61
62function operation2() {
63    throw new Error('Operation 2 failed');
64}
65
66try {
67    operation1();
68} catch (error) {
69    console.error('Chained error:', error.message);
70    console.error('Caused by:', error.cause.message);
71}
72
73// Method 4: Error handling middleware
74function errorHandler(error, context) {
75    console.error('Error in', context, ':', error.message);
76    // Log to service, send notification, etc.
77}
78
79function riskyOperation() {
80    try {
81        throw new Error('Operation failed');
82    } catch (error) {
83        errorHandler(error, 'riskyOperation');
84        throw error;
85    }
86}