stats-accumulator/dist/esm/index.js

A simple tool for calculating incremental stats on numeric streams. Forked from https://github.com/brycebaril/stats-incremental

const pf = Number.parseFloat || parseFloat;
const isString = (x)=>Object.prototype.toString.call(x) === '[object String]';
let Stats = class Stats {
    update(value) {
        const num = isString(value) ? pf(value) : value;
        if (Number.isNaN(num)) return;
        this.n++;
        this.min = Math.min(this.min, num);
        this.max = Math.max(this.max, num);
        this.sum += num;
        const prevMean = this.mean;
        this.mean = this.mean + (num - this.mean) / this.n;
        this.q = this.q + (num - prevMean) * (num - this.mean);
    }
    variance() {
        return this.q / this.n;
    }
    stddev() {
        return Math.sqrt(this.q / this.n);
    }
    toJSON() {
        if (this.n === 0) return null;
        return {
            n: this.n,
            min: this.min,
            max: this.max,
            sum: this.sum,
            mean: this.mean,
            variance: this.variance(),
            stddev: this.stddev()
        };
    }
    constructor(){
        this.n = 0;
        this.min = Number.MAX_VALUE;
        this.max = -Number.MAX_VALUE;
        this.sum = 0;
        this.mean = 0;
        this.q = 0;
    }
};
export { Stats as default };