无法将功能识别为功能？

Question

store.changes takes a function as an argument. test takes an object and its property as an argument:

store.changes(test(this, 'posts'))

function test (obj, prop) {
  store.find().then(posts => {
    obj[prop] = _.map(posts.rows, (post) => post.doc)
  })
}

store.changes = (func) => {
  return db.changes({
    since: 'now',
    live: true
  }).on('change', func)
}

But for some reason store.changes ins't recognizing test(this, 'posts') as a function, it throws the following error:

Uncaught TypeError: listener must be a function

Why is this?

Answer 1

You're passing the result of a call, undefined - not a function. I believe you are looking for

store.changes(() => test(this, 'posts'));