$ npm install regex-mobile-viewportRegex for checking HTML has a mobile meta-viewport
Where a mobile meta-viewport is correctly uses width=device-width and initial-scale=1 in the viewport meta tag.
$ npm install --save regex-mobile-viewport
var regexmobileviewport = require('regex-mobile-viewport');
regexmobileviewport().test('<meta name="viewport" content="width=device-width, initial-scale=1">');
//=> true
regexmobileviewport().test('<meta name="viewport" content="width=device-width, initial-scale=1.0">');
//=> true
regexmobileviewport().test('<meta name="viewport">');
//=> false
MIT © Addy Osmani