knex async modify

knex-async-modify.js

const before = (target, f) => {
    const then = target.then.bind(target)
    target.then = (resolve, reject) =>
        f(target).then(() => then(resolve, reject), reject)
    return target
}

Knex.QueryBuilder.extend('amodify', function (f) {
    const q = this
    const clone = this.clone.bind(this)
    before(q, f)
    this.clone = function () {
        const cloned = clone()
        before(cloned, f)
        return cloned
    }
    return this
})