@jetshop/core/experiments/selectExperimentVariant.js

function selectExperimentVariant(config, selectedVariant) {
    // If no experiment is configured, do nothing.
    if (!config) {
        return null;
    }
    // A valid cookie has the format xxxxxxxx.n where the first part is the experiment id and the second part is the variant index
    const parts = (selectedVariant || '').split('.');
    if (parts.length === 2) {
        const [experiment, variant] = parts;
        // Make sure the cookie refers to the currently configured experiment
        if (experiment === config.experimentId) {
            // Make sure that the variant index is withing the amount of variants we have configured
            if (parseInt(variant, 10) < config.variantWeights.length) {
                return selectedVariant;
            }
        }
    }
    const totalWeights = config.variantWeights.reduce((sum, cur) => sum + cur, 0);
    const absoluteWeights = config.variantWeights.map(weight => weight / totalWeights);
    // We either have no previous cookie, or an invalid one, so let's select a variant and set up the cookie
    const randomValue = Math.random();
    const variantCount = absoluteWeights.length;
    let i = 0, sum = 0;
    for (; i < variantCount; i++) {
        if (randomValue < sum + absoluteWeights[i]) {
            break;
        }
        else {
            sum += absoluteWeights[i];
        }
    }
    return `${config.experimentId}.${i}`;
}
export default selectExperimentVariant;
//# sourceMappingURL=selectExperimentVariant.js.map