node.js计算子网址数

Question

i'm very new to node.js, was trying to do as in the example below, but there is a problem with my code that I couldn't figure it out

example if

/add/1/1 -> should show in the page 2

/add/2/3 -> should show in the page 5

/sub/1/1 -> should show in the page 0

/sub/5/2 -> should show in the page 3

 var http = require('http') http.createServer(function(req, res){ var parts = req.url.split("/"), op = parseInt(parts[1]), a = parseInt(parts[2], 10), b = parseInt(parts[3], 10); var result = op ? op(a,b) : "Error"; res.writeHead(200, {'Content-Tybe': 'text/plain'}); res.end("" + result); }).listen(3000, "127.0.0.1"); 

Answer 1

In your code op is not a function. You must use eval(op) .

The rest of the code (accessing parameters) can be easily done using Express

const express = require('express')
const app = express()

app.get('/:op/:firstParam/:secondParam', function (req, res) {
  var op = req.params.op
  var a  = parseInt(req.params.firstParam)
  var b  = parseInt(req.params.secondParam)

  var result = eval(op)(a,b)
  res.send('result: ' + result)
})

function sum(a, b) {
  return a + b
}

function sub(a, b) {
  return a - b
}

app.listen(3000)

( Note : this example code will not work if you pass undefiend functions like foo ie http://localhost:3000/foo/8/2 . Add proper checks when calling eval(op) based on your specific needs)