send/app/experiments.js
2017-12-05 14:06:40 -08:00

69 lines
1.8 KiB
JavaScript

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);
}
}
}