should I replace wct-istanbul by WCT-istanbub in order to estimate how much polymer web compnents is test coveraged - polymer

Question

There is some similiarity between my question and How to measure common coverage for Polymer components + .js files?. Nevertheless, it is accepted as answer "split to .js files and include it to components" in order to use wct-istanbul and all my web components and tests are in .html files (the javascript is inside of each .html file).
My straight question is: can I still use wct-istambul to check how much from my code is covered by tests? If so, what is wrong in configuration described bellow? If not, is wct-istanbub planned to replace wct-istanbul for polymer projects?
package.json
"polyserve": "^0.18.0",
"web-component-tester": "^6.0.0",
"web-component-tester-istanbul": "^0.10.0",
...
wct.conf.js
var path = require('path');
var ret = {
'suites': ['test'],
'webserver': {
'pathMappings': []
},
'plugins': {
'local': {
'browsers': ['chrome']
},
'sauce': {
'disabled': true
},
"istanbul": {
"dir": "./coverage",
"reporters": ["text-summary", "lcov"],
"include": [
"/*.html"
],
"exclude": [
],
thresholds: {
global: {
statements: 100
}
}
}
}
};
var mapping = {};
var rootPath = (__dirname).split(path.sep).slice(-1)[0];
mapping['/components/' + rootPath + '/bower_components'] = 'bower_components';
ret.webserver.pathMappings.push(mapping);
module.exports = ret;
Well, I tried WCT-istanbub (https://github.com/Bubbit/wct-istanbub) which seams to be a temporary workaround (Code coverage of Polymer Application with WCT), it works.
wct.conf.js
"istanbub": {
"dir": "./coverage",
"reporters": ["text-summary", "lcov"],
"include": [
"**/*.html"
],
"exclude": [
"**/test/**",
"*/*.js"
],
thresholds: {
global: {
statements: 100
}
}
}
...
and the result is
...
chrome 66 RESPONSE quit()
chrome 66 BrowserRunner complete
Test run ended with great success
chrome 66 (2/0/0)
=============================== Coverage summary ===============================
Statements : 21.18% ( 2011/9495 )
Branches : 15.15% ( 933/6160 )
Functions : 18.08% ( 367/2030 )
Lines : 21.14% ( 2001/9464 )
================================================================================
Coverage for statements (21.18%) does not meet configured threshold (100%)
Error: Coverage failed