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import { compose } from './compose.js'import { identity } from './identity.js'import { inc } from './inc.js'import { lensProp } from './lensProp.js'import { over } from './over.js'import { set } from './set.js'import { view } from './view.js'
const testObj = {  a : 1,  b : 2,  c : 3,}
test('focuses object the specified object property', () => {  expect(view(lensProp('a'), testObj)).toBe(1)})
test('returns undefined if the specified property does not exist', () => {  expect(view(lensProp('X'), testObj)).toBeUndefined()})
test('sets the value of the object property specified', () => {  expect(set(    lensProp('a'), 0, testObj  )).toEqual({    a : 0,    b : 2,    c : 3,  })})
test('adds the property to the object if it doesn\'t exist', () => {  expect(set(    lensProp('d'), 4, testObj  )).toEqual({    a : 1,    b : 2,    c : 3,    d : 4,  })})
test('applies function to the value of the specified object property', () => {  expect(over(    lensProp('a'), inc, testObj  )).toEqual({    a : 2,    b : 2,    c : 3,  })})
test('applies function to undefined and adds the property if it doesn\'t exist', () => {  expect(over(    lensProp('X'), identity, testObj  )).toEqual({    a : 1,    b : 2,    c : 3,    X : undefined,  })})
test('can be composed', () => {  const nestedObj = {    a : { b : 1 },    c : 2,  }  const composedLens = compose(lensProp('a'), lensProp('b'))
  expect(view(composedLens, nestedObj)).toBe(1)})
test('set s (get s) === s', () => {  expect(set(    lensProp('a'), view(lensProp('a'), testObj), testObj  )).toEqual(testObj)})
test('get (set s v) === v', () => {  expect(view(lensProp('a'), set(    lensProp('a'), 0, testObj  ))).toBe(0)})
test('get (set(set s v1) v2) === v2', () => {  expect(view(lensProp('a'),    set(      lensProp('a'), 11, set(        lensProp('a'), 10, testObj      )    ))).toBe(11)})