get-script-tag-vars
v1.1.2
Published
Parse given HTML, look for `script` tags and extract values for given variables.
Downloads
4
Readme
get-script-tag-vars 
Parse given HTML, look for script tags and extract values for given variables.
Intended use case is to help with integration testing server-rendered apps - more
specifically, to enable checking variables like __INITIAL_STATE__.
How it works
Uses cheerio to grab all the script tags, parses them with esprima, and then
uses estraverse to find variable declarations and assignments. When such a node
is found, uses escodegen to generate a string, which is then evaluated with
Node's vm.
Usage
This module exports a function, getScriptTagVars. First parameter is the HTML,
and the second one is either a string if you only want to check a single variable,
or an array if multiple.
const getScriptTagVars = require('get-script-tag-vars')
let html = '<html><script>window.foo=42; var bar="bar"</script></html>'
let foo = getScriptTagVars(html, 'window.foo') // => 42
let bar = getScriptTagVars(html, 'bar') // => 'bar'
let obj = getScriptTagVars(html, ['window.foo', 'bar', 'baz'])
// => { 'window.foo': 42, 'bar': 'bar', 'baz': undefined }More examples in ./test.js.
Example
const getScriptTagVars = require('get-script-tag-vars')
const assert = require('assert')
const request = require('request-promise-native')
describe('Server-side rendering - initial state', () => {
it('should have "foo" set', (done) => {
request('foo/home').then(html => {
let initialState = getScriptTagVars(html, '__INITIAL_STATE__')
assert.deepEqual(initialState.foo, {
foo: 'some value'
})
done()
}).catch(ex => done(ex))
})
})