I have a simple express code which adds two numbers :
const express = require('express')
const bodyParser = require('body-parser')
const app = express()
const port = 3000
app.use(bodyParser.urlencoded({ extended: true }))
app.get('/', (req, res) => {
res.sendFile(__dirname + "/index.html")
})
app.post("/", (req, res) => {
let n1 = req.body.num1 //these n1 and n2 are coming from inex.html
let n2 = req.body.num2
let result = Number(n1) + Number(n2)
res.send("" + result)
})
app.listen(port, () => {
console.log("Server is running at port 3000")
})
In res.send if I removed the empty string and type only res.send(result) the code returns error :
RangeError [ERR_HTTP_INVALID_STATUS_CODE]: Invalid status code: 5
at new NodeError (node:internal/errors:372:5)
at ServerResponse.writeHead (node:_http_server:275:11)
at ServerResponse._implicitHeader (node:_http_server:266:8)
at ServerResponse.end (node:_http_outgoing:871:10)
at ServerResponse.send (C:\Users\Vandana Singh Bondil\OneDrive\Desktop\Lokesh\calculator\node_modules\express\lib\response.js:232:10)
at C:\Users\Vandana Singh Bondil\OneDrive\Desktop\Lokesh\calculator\calculator.js:17:9
at Layer.handle [as handle_request] (C:\Users\Vandana Singh Bondil\OneDrive\Desktop\Lokesh\calculator\node_modules\express\lib\router\layer.js:95:5)
at next (C:\Users\Vandana Singh Bondil\OneDrive\Desktop\Lokesh\calculator\node_modules\express\lib\router\route.js:144:13)
at Route.dispatch (C:\Users\Vandana Singh Bondil\OneDrive\Desktop\Lokesh\calculator\node_modules\express\lib\router\route.js:114:3)
at Layer.handle [as handle_request] (C:\Users\Vandana Singh Bondil\OneDrive\Desktop\Lokesh\calculator\node_modules\express\lib\router\layer.js:95:5)
Can anyone tell me why the code works???
Because send requires body to be...
...a
Bufferobject, aString, an object,Boolean, or anArray.
Numbers aren't in that list, but strings are. Although it's undocumented in v4 (onwards), in v3 you could pass a response status code (like 200 or 404) as the first argument, and apparently it still supports doing that (despite being undocumented) in the version you're using, probably to support legacy projects. 5 isn't a valid response status code, so you get the error. You have to convert your number to string. "" + result is one way to do that. Others are String(result) or result.toString().