Variables defined in a Nightmare script cannot be closed over using .evaluate() since the enclosing scope where the .evaluate() function is defined is not the scope where the function is actually executed. Consider:
var selector = 'a';
nightmare
.goto('http://yahoo.com')
.type('form[action*="/search"] [name=p]', 'github nightmare')
.click('form[action*="/search"] [type=submit]')
.wait('#main')
.evaluate(function() {
return document.querySelector(selector)
.href;
})
.then((href) => {
//do something with href...
})
...
};The .evaluate() function is stringified and passed to Electron where it is parsed back into a function and finally executed in the site client context. This means the original reference to selector is lost, and will be undefined when executed. The selector variable needs to be passed along with the function in order to work:
var selector = 'a';
nightmare
.goto('http://yahoo.com')
.type('form[action*="/search"] [name=p]', 'github nightmare')
.click('form[action*="/search"] [type=submit]')
.wait('#main')
.evaluate(function(selector) {
return document.querySelector(selector)
.href;
}, selector)
.then((href) => {
//do something with href...
})
...
};