Calculates the difference between two arrays, without filtering duplicate values.

Calculate array difference in Javascript.js

// 17% faster than using filter on set

function difference(a, b) {
    const s = new Set(b)
    const result = []
    for (const x of a) {
        if (!s.has(x)) {
            result.push(x)
        }
    }
    return result
}
difference([1, 2, 3, 3], [1, 2, 4])