@webpack-blocks/core/lib/__tests__/group.test.js

Functional approach to compose your webpack config.

import test from 'ava'
import sinon from 'sinon'
import group from '../group'

test('group() merges the blocks', t => {
  const block1 = createTestBlock1()
  const block2 = createTestBlock2()
  const block3 = createTestBlock3()

  const grouped = group([block1, block2, block3])
  t.is(typeof grouped, 'function')

  const resultingConfig = grouped({}, {})({})
  t.deepEqual(resultingConfig, {
    distinct1: 'distinct1',
    distinct2: 'distinct2',
    distinct3: 'distinct3',
    shared: 'shared3'
  })

  t.is(block1.callCount, 1)
  t.is(block2.callCount, 1)
  t.is(block3.callCount, 1)
})

test('group() merges pre hooks', t => {
  const block1 = createTestBlock1()
  const block2 = createTestBlock2()
  const block3 = createTestBlock3()

  const grouped = group([block1, block2, block3])

  // there are no hooks set on block2 and block3's hook is an array
  t.deepEqual(grouped.pre, [block1.pre, block3.pre[0]])
  t.is(block1.pre.callCount, 0)
  t.is(block3.pre[0].callCount, 0)
})

test('group() merges post hooks', t => {
  const block1 = createTestBlock1()
  const block2 = createTestBlock2()
  const block3 = createTestBlock3()

  const grouped = group([block1, block2, block3])

  // there are no hooks set on block2 and block3's hook is an array
  t.deepEqual(grouped.post, [block1.post, block3.post[0]])
  t.is(block1.post.callCount, 0)
  t.is(block3.post[0].callCount, 0)
})

// Single-function pre & post hook
function createTestBlock1() {
  const setter = () => prevConfig => ({
    ...prevConfig,
    distinct1: 'distinct1',
    shared: 'shared1'
  })

  const pre = () => {}
  const post = () => prevConfig => ({
    ...prevConfig,
    post1: 'post1',
    postShared: 'shared1'
  })

  return Object.assign(sinon.spy(setter), {
    pre: sinon.spy(pre),
    post: sinon.spy(post)
  })
}

// No hooks
function createTestBlock2() {
  const setter = () => prevConfig => ({
    ...prevConfig,
    distinct2: 'distinct2',
    shared: 'shared2'
  })

  return sinon.spy(setter)
}

// Array-of-functions pre & post hook
function createTestBlock3() {
  const setter = () => prevConfig => ({
    ...prevConfig,
    distinct3: 'distinct3',
    shared: 'shared3'
  })

  const pre = () => {}
  const post = () => prevConfig => ({
    ...prevConfig,
    post3: 'post3',
    postShared: 'shared3'
  })

  return Object.assign(sinon.spy(setter), {
    pre: [sinon.spy(pre)],
    post: [sinon.spy(post)]
  })
}