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Express.js - handle exception
10 points
In this article, we would like to show how to handle exception in Express.js.
By exceptions handling we are able to:
- send to user safe message when exception occurred hiding exception's sensitive information,
- display in console details about occured exception.
Quick solution:
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const express = require('express');2
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const app = express();4
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// app routes6
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// ...8
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app.get('/path/to/endpoint', (request, response, next) => {10
try {11
// Some logic here ...12
} catch (error) {13
return next(error);14
}15
});16
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// ...18
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// error routes20
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app.use((error, request, response, next) => {22
response.status(500).send('Internal server error!');23
next(error);24
});25
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// server running27
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app.listen(8080, () => console.log(`Server is listening on port 8080.`));
In this section, you can find reusable functions that let to simplyfy your's application source code.
index.js file:
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const express = require('express');2
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const {tryGet, tryPost, mapErrors} = require('./request');4
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const app = express();6
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// ...8
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tryGet(app, '/path/to/endpoint-1', async (request, response) => {10
// Some logic here ...11
});12
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tryPost(app, '/path/to/endpoint-2', async (request, response) => {14
// Some logic here ...15
});16
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// ...18
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mapErrors(app);20
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app.listen(8080, () => console.log(`Server is listening on port 8080.`));
request.js file:
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exports.tryGet = (app, path, handler) => {2
return app.get(path, async (request, response, next) => {3
try {4
await handler(request, response);5
} catch (error) {6
return next(error);7
}8
});9
};10
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exports.tryPost = (app, path, handler) => {12
return app.post(path, async (request, response, next) => {13
try {14
await handler(request, response);15
} catch (error) {16
return next(error);17
}18
});19
};20
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exports.mapErrors = (app) => {22
app.use((error, request, response, next) => {23
console.error(`Method: ${request.method}, URL: ${request.protocol}://${request.hostname}${request.url}`);24
response25
.status(500)26
.json({27
result: false,28
message: 'Internal server error!'29
});30
next(error);31
});32
};
