Editor.test.js

/* globals describe, it, expect */
const {edit, edits, DELETED} = require('./Editor')

describe('editor', () => {
  it('supports simple edits', () => {
    const e = edit({ x: 5 })
    e.x = 10
    e.y = 20
    expect(e.y).toEqual(20)
    expect(Object.keys(e)).toEqual(['x', 'y'])
    expect(e).toEqual({ x: 10, y: 20 })
  })

  it('leaves src untouched', () => {
    const src = { x: 5 }
    const e = edit(src)
    e.x = 10
    e.y = 20
    expect(src).toEqual({ x: 5 })
  })

  it('supports deep edits', () => {
    const src = { a: { b: { c: 1 } } }
    const e = edit(src)
    e.a.b.d = 2
    expect(e.a.b.d).toEqual(2)
    expect(e).toEqual({ a: { b: { c: 1, d: 2 } } })

    // still leaves src unchanged
    expect(src).toEqual({ a: { b: { c: 1 } } })
  })

  it('edits can extract edits from an edit object', () => {
    const e = edit({})
    expect(edits(e)).toBeUndefined()

    e.a = 10
    e.b = { c: 1 }
    expect(edits(e)).toEqual({ a: 10, b: { c: 1 } })
  })

  it('computes the smallest edit possible', () => {
    const e = edit({ a: { b: { c: 1 } } })
    e.a.e = 2
    expect(edits(e)).toEqual({ a: { e: 2 } })
  })

  it('exports DELETED Symbol', () => {
    expect(DELETED).toBeDefined()
  })

  it('supports deletion', () => {
    const src = {a: 1}
    const e = edit(src)
    delete e.a
    expect(e.a).toBeUndefined()
    expect(src.a).toEqual(1)
    expect(Object.keys(edits(e))).toEqual(['a'])
  })

  it('sees deletion when edit is being done on an Edit object', () => {
    const src = {a: 1}
    const e1 = edit(src)
    delete e1.a
    const e2 = edit(e1)
    expect(e2.a).toBeUndefined()
    expect(src.a).toEqual(1)
  })

  it('deletion on deep object works', () => {
    const src = {}
    const e1 = edit(src)
    e1.x = {a: 1}
    delete e1.x.a
    expect(e1.x.a).toBeUndefined()
    expect(Object.keys(e1.x)).toEqual([])
    expect(e1.x).toEqual({})

    expect(edits(e1)).toEqual({x: {a: DELETED}})
  })
})