withMemoization

withMemoization.js

function withMemoization(func, identifierFunc) {
  const cache = new Map()

  return (...args) => {
    const identifier = identifierFunc(...args)
    if (cache.has(identifier)) {
      return cache.get(identifier)
    }
    const result = func(...args)
    cache.set(identifier, result)
    return result
  }
}

/* EXAMPLE

const queryPost = withMemoization(
  $.query,
  ($post, selector) => $post.getAttribute('data-id') + '-' + selector
)
*/