Function doesnt return the code while using map() in NodeJS

Question

What's wrong here? Unable to get the output. "ReplaceHTML" doesn't return the required HTML code. In the replaceHTML function when I hit console.log before the 'return'(which I commented), then it gives the perfect answer but doesn't return anything after that. What's the reason? Any suggestion or help is most welcome.

const fs = require("fs");
const http = require("http");

const index = fs.readFileSync("index.html", "utf-8");
const dataIndex = fs.readFileSync("data.html", "utf-8");
const data = fs.readFileSync("json.json", "utf-8");
const objData = JSON.parse(data);

const replaceHTML = (temp, product) => {
  let output = temp.replace(/{%%NAME%%}/g, product.name);
  output = output.replace(/{%%USERNAME%%}/g, product.username);
  output = output.replace(/{%%EMAIL%%}/g, product.email);
  // console.log(output);
  return output;
};

const mainData = (temp, code) => {
  return temp.replace(/{%%MAINDATA%%}/g, code);
};

const server = http.createServer((req, res) => {
  const htmlData = objData
    .map((data) => {
      replaceHTML(dataIndex, data);
    })
    .join("");
  console.log(htmlData);

  let finalData = mainData(index, htmlData);
  res.end(finalData);
});

server.listen("3000", "127.0.0.1");

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    {%%MAINDATA%%}
  </body>
</html>

<div>
  <h1>Name: {%%NAME%%}</h1>
  <h2>UserName: {%%USERNAME%%}</h2>
  <p>Email: {%%EMAIL%%}</p>
</div>

The map does not return anything – evolutionxbox Aug 30 '22 at 14:47 — evolutionxbox, Aug 30 '22 at 14:47

score 1 · Accepted Answer · answered Aug 30 '22 at 14:46

1

You are not returning anything from the .map iterator:

const htmlData = objData.map((data) => {
   replaceHTML(dataIndex, data);
})

Just add the missing return:

const htmlData = objData.map((data) => {
   return replaceHTML(dataIndex, data);
})

Or remove the curly brackets:

const htmlData = objData.map((data) => replaceHTML(dataIndex, data))

answered Aug 30 '22 at 14:46

moonwave99

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Oh my goodness how could i miss this :( – Abhishek Srinivasan Aug 30 '22 at 14:48

Function doesnt return the code while using map() in NodeJS

1 Answers1