cosineSimilarity.js

var cosineSimilarity = (A, B)=> {
    let dotProduct = (a, b)=> {
        if(a.length!=b.length) throw Error("Bad vector");
        let sum = 0;
        for(let i = 0; i<a.length; i++) {
            sum+=(a[i]*b[i]);
        }
        return sum;
    };
    let magnitude = (a)=> {
        let squareSum = 0;
        for(let i of a) {
            squareSum+=i**2;
        }
        return squareSum**0.5
    };
    let AdotB = dotProduct(A, B);
    let Amag = magnitude(A);
    let Bmag = magnitude(B);
    return AdotB/(Amag*Bmag);
};