mathjs/test/function/string/format.test.js

// test format
const assert = require('assert')
const math = require('../../../src/main')

describe('format', function () {
  it('should format numbers', function () {
    assert.equal(math.format(2 / 7), '0.2857142857142857')
    assert.equal(math.format(0.10400), '0.104')
    assert.equal(math.format(2.3), '2.3')
    assert.equal(math.format(2.3e6), '2.3e+6')
  })

  it('should format strings', function () {
    assert.equal(math.format('hello'), '"hello"')
  })

  it('should format arrays', function () {
    assert.equal(math.format([[1, 2], [3, 4]]), '[[1, 2], [3, 4]]')
    const array = [[math.unit(2 / 3, 'm'), 2 / 7], ['hi', math.complex(2, 1 / 3)]]
    assert.equal(math.format(array, 5), '[[0.66667 m, 0.28571], ["hi", 2 + 0.33333i]]')
  })

  it('should format complex values', function () {
    assert.equal(math.format(math.divide(math.complex(2, 5), 3)), '0.6666666666666666 + 1.6666666666666667i')
    assert.equal(math.format(math.divide(math.complex(2, 5), 3), 5), '0.66667 + 1.6667i')
    assert.equal(math.format(math.divide(math.complex(2, 5), 3), {notation: 'fixed', precision: 1}), '0.7 + 1.7i')
    assert.equal(math.format(math.divide(math.complex(6, 9), 3), {notation: 'fixed'}), '2 + 3i')

    assert.equal(math.format(math.complex(NaN, NaN)), 'NaN + NaNi')
    assert.equal(math.format(math.complex(Infinity, Infinity)), 'Infinity + Infinityi')
    assert.equal(math.format(math.complex(Infinity, -Infinity)), 'Infinity - Infinityi')
  })

  describe('precision', function () {
    it('should format numbers with given precision', function () {
      assert.equal(math.format(1 / 3), '0.3333333333333333')
      assert.equal(math.format(1 / 3, 3), '0.333')
      assert.equal(math.format(1 / 3, 4), '0.3333')
      assert.equal(math.format(1 / 3, 5), '0.33333')
      assert.equal(math.format(math.complex(1 / 3, 2), 3), '0.333 + 2i')
    })

    it('should format complex numbers with given precision', function () {
      assert.equal(math.format(math.complex(1 / 3, 1 / 3), 3), '0.333 + 0.333i')
      assert.equal(math.format(math.complex(1 / 3, 1 / 3), 4), '0.3333 + 0.3333i')
    })

    it('should format matrices with given precision', function () {
      assert.equal(math.format([1 / 3, 1 / 3], 3), '[0.333, 0.333]')
      assert.equal(math.format([1 / 3, 1 / 3], 4), '[0.3333, 0.3333]')
      assert.equal(math.format(math.matrix([1 / 3, 1 / 3]), 4), '[0.3333, 0.3333]')
    })

    it('should format units with given precision', function () {
      assert.equal(math.format(math.unit(2 / 3, 'm'), 3), '0.667 m')
      assert.equal(math.format(math.unit(2 / 3, 'm'), 4), '0.6667 m')
    })

    it('should format ranges with given precision', function () {
      assert.equal(math.format(new math.type.Range(1 / 3, 4 / 3, 2 / 3), 3), '0.333:0.667:1.33')
    })
  })

  describe('engineering notation', function () {
    it('should format positive single digit to engineering notation', function () {
      assert.equal(math.format(3, { notation: 'engineering' }), '3e+0')
    })
    it('should format positive two digits to engineering notation', function () {
      assert.equal(math.format(30, { notation: 'engineering' }), '30e+0')
    })
    it('should format positive three digits to engineering notation', function () {
      assert.equal(math.format(300, { notation: 'engineering' }), '300e+0')
    })
    it('should format positive four digits to engineering notation', function () {
      assert.equal(math.format(3000, { notation: 'engineering' }), '3e+3')
    })
    it('should format positive uneven four digits to engineering notation', function () {
      assert.equal(math.format(3001, { notation: 'engineering' }), '3.001e+3')
    })
    it('should format positive uneven ten digits to engineering notation', function () {
      assert.equal(math.format(3741293481, { notation: 'engineering' }), '3.741293481e+9')
    })
    it('should format negative uneven ten digits to engineering notation', function () {
      assert.equal(math.format(-3741293481, { notation: 'engineering' }), '-3.741293481e+9')
    })
    it('should format positive single digit floating point numbers to engineering notation', function () {
      assert.equal(math.format(0.1, { notation: 'engineering' }), '100e-3')
    })
    it('should format positive two digit floating point numbers to engineering notation', function () {
      assert.equal(math.format(0.01, { notation: 'engineering' }), '10e-3')
    })
    it('should format positive three digit floating point numbers to engineering notation', function () {
      assert.equal(math.format(0.003, { notation: 'engineering' }), '3e-3')
    })
    it('should format positive repeating three digit floating point numbers to engineering notation with precision', function () {
      assert.equal(math.format(1 / 3, { precision: 3, notation: 'engineering' }), '333e-3')
    })
    it('should format positive seven digit floating point numbers to engineering notation', function () {
      assert.equal(math.format(0.1234567, { notation: 'engineering' }), '123.4567e-3')
    })
    it('should format negative single digit floating point numbers to engineering notation', function () {
      assert.equal(math.format(-0.1, { notation: 'engineering' }), '-100e-3')
    })
    it('should format positive floating point number to engineering notation', function () {
      assert.equal(math.format(13308.0333333333, { precision: 11, notation: 'engineering' }), '13.308033333e+3')
    })
  })

  describe('bignumber', function () {
    const bigmath = math.create({precision: 20}) // ensure the precision is 20 digits

    it('should format big numbers', function () {
      assert.equal(math.format(bigmath.bignumber(2).dividedBy(7)), '0.28571428571428571429')
      assert.equal(math.format(bigmath.bignumber(0.10400)), '0.104')
      assert.equal(math.format(bigmath.bignumber(2.3)), '2.3')
      assert.equal(math.format(bigmath.bignumber(2.3e6)), '2.3e+6')
    })

    it('should format big numbers with given precision', function () {
      const oneThird = bigmath.bignumber(1).div(3)
      assert.equal(bigmath.format(oneThird), '0.33333333333333333333') // 20 digits
      assert.equal(bigmath.format(oneThird, 3), '0.333')
      assert.equal(bigmath.format(oneThird, 4), '0.3333')
      assert.equal(bigmath.format(oneThird, 5), '0.33333')
      assert.equal(bigmath.format(oneThird, 18), '0.333333333333333333')
    })
  })

  it('should throw an error on wrong number of arguments', function () {
    assert.throws(function () { math.format() }, /TypeError: Too few arguments/)
    assert.throws(function () { math.format(1, 2, 3) }, /TypeError: Too many arguments/)
  })

  it('should LaTeX format', function () {
    const expression = math.parse('format(1)')
    assert.equal(expression.toTex(), '\\mathrm{format}\\left(1\\right)')
  })
})