Brtdku

I'm getting json data and in the main page. Before loading json data the page should display loading text. After json data loaded completely it should display json data completely.

var express = require('express');

'use strict';

var https = require('https');

var app =  express();

var request = require('request');

var bodyParser =require('body-parser');

var task = ;

app.set('view engine', 'ejs');

app.use(bodyParser.urlencoded({ extended: true }));

app.listen(3000, function(){

console.log('Example app listening on port 3000 !');

});

function initialize() {

var options = {

url: 'https://jsonplaceholder.typicode.com/posts',

headers: {'User-Agent': 'request'}

};

// Return new promise 

return new Promise(function(resolve, reject) {

// Do async job

request.get(options, function(err, resp, body) {

if (err) {

reject(err);

} else {

resolve(JSON.parse(body));

}

})

})

}

app.get('/', function(req, res){

if(task.length === 0){

var initializePromise = initialize();

initializePromise.then(function(result) {

task = result;

// res.redirect('/test');

console.log("task initialized");

if(counter ===0){

res.render('index', {task: task.splice(0, lNum), loading: false});

}

}, function(err) { console.log(err); });       

}else{

console.log("task already initialized");

}

if(task.length ===0){

res.render('index', {task: null, loading: true});

}else{

res.render('index', {task: task, loading: false });

}  

});

When I run script. It gives me following error

Example app listening on port 3000 !

task initialized

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client

    at validateHeader (_http_outgoing.js:503:11)

    at ServerResponse.setHeader (_http_outgoing.js:510:3)

    at ServerResponse.header (C:UsersCrustalmaaDocumentssassprojectreactappjobnode_modulesexpresslibresponse.js:767:10)

    at ServerResponse.send (C:UsersCrustalmaaDocumentssassprojectreactappjobnode_modulesexpresslibresponse.js:170:12)

    at done (C:UsersCrustalmaaDocumentssassprojectreactappjobnode_modulesexpresslibresponse.js:1004:10)

    at tryHandleCache (C:UsersCrustalmaaDocumentssassprojectreactappjobnode_modulesejslibejs.js:257:5)

    at View.exports.renderFile [as engine] (C:UsersCrustalmaaDocumentssassprojectreactappjobnode_modulesejslibejs.js:482:10)

    at View.render (C:UsersCrustalmaaDocumentssassprojectreactappjobnode_modulesexpresslibview.js:135:8)

    at tryRender (C:UsersCrustalmaaDocumentssassprojectreactappjobnode_modulesexpresslibapplication.js:640:10)

    at Function.render (C:UsersCrustalmaaDocumentssassprojectreactappjobnode_modulesexpresslibapplication.js:592:3)

Task already initialized.

When I comment one of res.render method in app.get('/', function(){})
And I don't know how to redirect or update the index.ejs. in index.ejs

<% if(loading){%>

<p>Loading</p>

<%} else{%>

<% for( var i = 0; i < task.length; i++){ %>

<li><input type="checkbox" name="check" value="<%= task[i] %>" /> <%= task[i].id %> </li>

<% } } %>

<a href  = "/test">Load more</a>

When I run localhost:3000

after 2 seconds refresh the browser it gives me following result

and I don't want to manually refresh the browser. When content loading completed it automatically refresh or update content. How do I do that and fix the error message?