ruby 这是Array类的自定义“flatten”方法，仅用于测试。

Posted 2021-05-16

class Array
  def press
    each_with_object([]) do |elem, flat|
      flat.push(*(elem.respond_to?(:each_with_object) ? elem.press : elem))
    end
  end
end

### Specs

require 'spec_helper'

RSpec.describe Array do
  context '.press' do
    it 'flattens a nested array of integers' do
      nested = [[1, 2, [3]], 4]
      expect(nested.press).to eq([1, 2, 3, 4])
    end

    it 'flattens a nested array of arbitrary things' do
      object = Object.new
      nested = [[1, 2, [object]], '4']
      expect(nested.press).to eq([1, 2, object, '4'])
    end
  end
end