metalsmith-timestamp 
Add timestamp to html files
npm install --save metalsmith-timestampIf you haven't checked out Metalsmith before, head over to their website and check out the documentation.
If you are using the command-line version of Metalsmith, you can install via npm, and then add the
metalsmith-timestamp key to your metalsmith.json file:
{
"plugins": {
"metalsmith-timestamp": {}
}
}If you are using the JS Api for Metalsmith, then you can require the module and add it to your .use() directives:
var timestamp = require('metalsmith-timestamp');
metalsmith.use(timestamp(options));Type: String
Default: '%d %B %Y %H:%M:%S'
strftime date time format
MIT © Daniel Husar