import { expect } from 'chai'
import u from '../lib'

describe('u.ifElse', () => {
  it('does updates with the else if the predicate is false', () => {
    const object = { a: 0 }
    const result = u.ifElse(false, { b: 1 }, { b: 2 }, object)
    expect(result).to.eql({ a: 0, b: 2 })
  })

  it('updates with the true update if the predicate is true', () => {
    const object = { a: 0 }
    const result = u.ifElse(true, { b: 1 }, { b: 4 }, object)
    expect(result).to.eql({ a: 0, b: 1 })
  })

  it('will use the result of a function passed as a predicate', () => {
    const object = { a: 0 }
    const aIsThree = (x) => x.a === 3
    const result = u.ifElse(aIsThree, { b: 1 }, { b: 4 }, object)

    expect(result).to.eql({ a: 0, b: 4 })
  })

  it('can be partially applied', () => {
    const object = { a: 2 }
    const isEven = (x) => x % 2 === 0
    const inc = (x) => x + 1
    const dec = (x) => x - 1

    const result = u(
      {
        a: u.ifElse(isEven, inc, dec),
      },
      object
    )

    expect(result).to.eql({ a: 3 })
  })

  it('freezes the result', () => {
    expect(Object.isFrozen(u.ifElse(true, {}, {}, {}))).to.be.true
    expect(Object.isFrozen(u.ifElse(false, {}, {}, {}))).to.be.true
  })
})