import hash from 'string-hash'; const experiments = { XnN0idVWSxO6A0kiNkxzGw: { id: 'XnN0idVWSxO6A0kiNkxzGw', run: function(variant, state, emitter) { state.promo = variant === 1 ? 'blue' : 'grey'; emitter.emit('render'); }, eligible: function() { return ( !/firefox/i.test(navigator.userAgent) && document.querySelector('html').lang === 'en-US' ); }, variant: function(state) { return this.luckyNumber(state) > 0.5 ? 1 : 0; }, luckyNumber: function(state) { return luckyNumber( `${this.id}:${state.storage.get('testpilot_ga__cid')}` ); } } }; //Returns a number between 0 and 1 // eslint-disable-next-line no-unused-vars function luckyNumber(str) { return hash(str) / 0xffffffff; } function checkExperiments(state, emitter) { const all = Object.keys(experiments); const id = all.find(id => experiments[id].eligible(state)); if (id) { const variant = experiments[id].variant(state); state.storage.enroll(id, variant); experiments[id].run(variant, state, emitter); } } export default function initialize(state, emitter) { emitter.on('DOMContentLoaded', () => { const xp = experiments[state.query.x]; if (xp) { xp.run(+state.query.v, state, emitter); } }); if (!state.storage.get('testpilot_ga__cid')) { // first ever visit. check again after cid is assigned. emitter.on('DOMContentLoaded', () => { checkExperiments(state, emitter); }); } else { const enrolled = state.storage.enrolled.filter(([id, variant]) => { const xp = experiments[id]; if (xp) { xp.run(variant, state, emitter); } return !!xp; }); // single experiment per session for now if (enrolled.length === 0) { checkExperiments(state, emitter); } } }