als-statistics/lib/descriptive/weighted-mean.js

Modular JS statistics toolkit for Node.js and the browser: descriptive stats, correlations (Pearson/Spearman/Kendall), t-tests & ANOVA (Student/Welch), reliability (Cronbach’s alpha), regression (linear/logistic), clustering (DBSCAN/HDBSCAN), and table/co

function weightedMean(weights,values) {
   if (!Array.isArray(weights) || weights.length !== values.length) throw new Error("Weights must be an array of the same length as values");
   let wSum = 0, valSum = 0;
   for (let i = 0; i < values.length; i++) {
      wSum += weights[i];
      valSum += values[i] * weights[i];
   }
   return wSum === 0 ? 0 : valSum / wSum;
}

export default weightedMean