Question: How to update NPM?
npm install -g npm
Question: How to write in file through NodeJs?
For this, you need to use filesystem API.
var fs = require('fs'); //Create Object
var fileName='/tmp/myfile.txt';
var fileContent='Hello this is text message';
fs.writeFile(fileName, fileContent, function(err) {
if(err) {
return console.log('error:'+err);
}
console.log("Content saved in File successfully");
});
Question: How to check File Exist OR Not?
For this, you need to use filesystem API.
var fs = require('fs');
var fileName='/tmp/myfile.txt';
if (fs.existsSync(fileName)) {
console.log('File Exist');
}else{
console.log('File Does not Exist');
}
Question: How to remove a file?
For this, you need to use filesystem API.
var fs = require('fs');
var fileName='/tmp/myfile.txt';
fs.unlinkSync(fileName);
Question: How to read process EVN?
console.log(process.env)Output
{
ENV_NODE_CONSOLE: 'production',
DYNO: 'web.1',
PATH: '/app/vendor/node/bin:/app/bin:/app/node_modules/.bin:bin:node_modules/.bin:/usr/local/bin:/usr/bin:/bin',
PWD: '/app',
MONGOLAB_URI: 'mongodb://heroku_app14996339_A:PQrhCoawHlCQcpOQNRkBeEbXLXnhYNSz@ds043987.mongolab.com:43987/heroku_app14996339',
PS1: '[033[01;34m]',
NODE_ENV: 'production',
SHLVL: '1',
HOME: '/app',
NO_CLUSTER: 'true',
PORT: '24118',
_: '/app/vendor/node/bin/node'
}
Question: How to retrieve POST query parameters in Express?
app.post('/test-page', function(req, res) {
console.log(req.body);//here is post data
});
Question: How to encode a sting using base64_encode?
console.log(new Buffer("1").toString('base64')); //MQ==
Question: How to decode a sting using base64_decode?
console.log(new Buffer("MQ==", 'base64').toString('ascii'));//1
Question: How can I pretty-print JSON using node.js?
var testVar ='{ a:1, b:2, c:3 }, null, 4';
JSON.stringify(testVar);
Question: How to exit in Node.js?
process.exit().
Question: How to exit from unix terminal in Node.js?
ctr+c twice
