Load a new page when a function throws an error-CodePudding

I want to load a new error page when a function throws an error.

I want to show an error page whenever an error is thrown but the page is stuck at a loading screen, and there are error messages on my log. When getStockPoints throws an error and I export this function to app.js and call it there with try and catch block, then it catches the error but the page is just stuck at loading. I want it to go to an error page.

module.exports = {
  async getStocks () {
    return stocks
  },
  async getStockPoints (stockName, timestamp) {
    if (Math.random() < FAILUE_RATE) {
      throw new Error('Failed to generate stock data')
    }
    if (!stocks.includes(stockName)) {
      throw new Error(`Uknown stock ${stockName}`)
    }
    const timestamps = getTimestamps( timestamp, 10)
    return getSeries(stockName, timestamps).map((value, idx) => ({
      value,
      timestamp: timestamps[idx]
    }))
  }
}

I did the try-catch method and tried to load a new page but it does not work.

app.get('/stocks/:symbol', async (req, res) => {
  const { params: { symbol } } = req
  try{
    const data = await stocks.getStockPoints(symbol, new Date())
    res.render('stockPoints', {DATA: data})
  }
  catch(e){
    console.log("ERRORs: ")
    console.error(e)
  }
})

The page is stuck at a loading screen. Here is the error that I am getting:

Error: Uknown stock df
    at Object.getStockPoints (C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\stocks.js:47:13)
    at C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\app.js:24:31
    at Layer.handle [as handle_request] (C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\node_modules\express\lib\router\layer.js:95:5)
    at next (C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\node_modules\express\lib\router\route.js:144:13)
    at Route.dispatch (C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\node_modules\express\lib\router\route.js:114:3)
    at Layer.handle [as handle_request] (C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\node_modules\express\lib\router\layer.js:95:5)
    at C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\node_modules\express\lib\router\index.js:284:15
    at param (C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\node_modules\express\lib\router\index.js:365:14)
    at param (C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\node_modules\express\lib\router\index.js:376:14)
    at Function.process_params (C:\Users\talha_znbd0fl\Desktop\JavaScript-Challenge-master-main\JavaScript-Challenge-master-main\node_modules\express\lib\router\index.js:421:3)

CodePudding user response：

You are stuck at a loading page because your server never responds to the request. There are multiple functions you can call to serve a result, but if you likely want to render an error page. To do this, all you have to do is call res.render inside your exception handler. Just like this:

app.get('/stocks/:symbol', async (req, res) => {
  const { params: { symbol } } = req
  try{
    const data = await stocks.getStockPoints(symbol, new Date())
    res.render('stockPoints', {DATA: data})
  } catch (e){
    console.log("ERRORs: ")
    console.error(e)
    res.render('errorPage')
  }
})

Then, create the template errorPage. It can be anything, but here's something simple to get you started:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Error</title>
</head>
<body>
    <h1>An error occured</h1>
</body>
</html>