Node.js winston timestamp only shows timestamp of when the app started - node.js

Question

I implemented a Winston logger in Node.js but every time it prints something it prints the exact same timestamp. The timestamp it prints is the time that my app was run. Here is my code:
const logger = createLogger({
format: combine(
timestamp({
format: moment().utcOffset('-0400').format('YYYY-MM-DD HH:mm:ss.SSSS')
}),
prettyPrint()
),
transports: [
new transports.Console({
timestamp: function () {
var d = +new Date();
}
}),
new winston.transports.File({
filename: "error.log",
level: "error",
timestamp: function () {
var d = +new Date();
}
}),
new winston.transports.File({
filename: "combined.log",
json: false,
timestamp: function () {
var d = +new Date();
}
})
]
});

Answer 1

format: Either the format as a string accepted by the fecha module or a function that returns a formatted date. If no format is provided new Date().toISOString() will be used.
According to winston documentation, format can take either,
a string (date format - YYYY-MM-DD HH:mm:ss.SSSS) or,
a function which returns the formatted date
Modify the code to return the formatted date from a function
const logger = createLogger({
format: combine(
timestamp({
format: () => {
return moment().utcOffset('-0400').format('YYYY-MM-DD HH:mm:ss.SSSS')
}
}),
prettyPrint()
) ....
Reference winston logform documentation

Answer 2

When you include Winston, it usually defaults to adding a Console transport. In order to get timestamps to work in this default case, I needed to either:
Remove the console transport and add again with the timestamp
option.
Create your own Logger object with the timestamp option set to true
The first:
var winston = require('winston');
winston.remove(winston.transports.Console);
winston.add(winston.transports.Console, {'timestamp':true});
The second, and cleaner option:
var winston = require('winston');
var logger = new (winston.Logger)({
transports: [
new (winston.transports.Console)({'timestamp':true})
]
});