mathjs/test/expression/node/ArrayNode.test.js

// test ArrayNode
var assert = require('assert')
var approx = require('../../../tools/approx')
var math = require('../../../src/index')
var Node = math.expression.node.Node
var ConstantNode = math.expression.node.ConstantNode
var SymbolNode = math.expression.node.SymbolNode
var RangeNode = math.expression.node.RangeNode
var ArrayNode = math.expression.node.ArrayNode

describe('ArrayNode', function () {
  it('should create an ArrayNode', function () {
    var c = new ConstantNode(1)
    var a = new ArrayNode([c])
    var b = new ArrayNode([])
    assert(a instanceof ArrayNode)
    assert(b instanceof ArrayNode)
    assert.equal(a.type, 'ArrayNode')
    assert.equal(b.type, 'ArrayNode')
  })

  it('should have property isArrayNode', function () {
    var node = new ArrayNode([])

    assert(node.isArrayNode)
  })

  it('should throw an error when calling without new operator', function () {
    assert.throws(function () { ArrayNode() }, SyntaxError)
  })

  it('should throw an error on wrong constructor arguments', function () {
    assert.throws(function () { new ArrayNode(2) }, TypeError)
    assert.throws(function () { new ArrayNode([2, 3]) }, TypeError)
  })

  it('should evaluate an ArrayNode', function () {
    var c = new ConstantNode(1)
    var a = new ArrayNode([c])
    var b = new ArrayNode()

    assert.deepEqual(a.compile().eval(), math.matrix([1]))
    assert.deepEqual(b.compile().eval(), math.matrix([]))
  })

  it('should compile an ArrayNode and evaluate as Matrix', function () {
    var a = new ConstantNode(1)
    var b = new ConstantNode(2)
    var c = new ConstantNode(3)
    var d = new ConstantNode(4)
    var n = new ArrayNode([a, b, c, d])

    var expr = n.compile()
    assert.deepEqual(expr.eval(), math.matrix([1, 2, 3, 4]))
  })

  it('should compile an ArrayNode and evaluate as Array', function () {
    var mathArray = math.create({matrix: 'Array'})
    var a = new mathArray.expression.node.ConstantNode(1)
    var b = new mathArray.expression.node.ConstantNode(2)
    var c = new mathArray.expression.node.ConstantNode(3)
    var d = new mathArray.expression.node.ConstantNode(4)
    var n = new mathArray.expression.node.ArrayNode([a, b, c, d])
    var expr = n.compile()
    assert.deepEqual(expr.eval(), [1, 2, 3, 4])
  })

  it('should compile nested ArrayNodes', function () {
    var a = new ConstantNode(1)
    var b = new ConstantNode(2)
    var c = new ConstantNode(3)
    var d = new ConstantNode(4)

    var n2 = new ArrayNode([a, b])
    var n3 = new ArrayNode([c, d])
    var n4 = new ArrayNode([n2, n3])

    var expr = n4.compile()
    assert.deepEqual(expr.eval(), math.matrix([[1, 2], [3, 4]]))
  })

  it('should find an ArrayNode', function () {
    var a = new ConstantNode(1)
    var b = new SymbolNode('x')
    var c = new ConstantNode(2)
    var d = new ArrayNode([a, b, c])

    assert.deepEqual(d.filter(function (node) { return node instanceof ArrayNode }), [d])
    assert.deepEqual(d.filter(function (node) { return node instanceof SymbolNode }), [b])
    assert.deepEqual(d.filter(function (node) { return node instanceof RangeNode }), [])
    assert.deepEqual(d.filter(function (node) { return node instanceof ConstantNode }), [a, c])
    assert.deepEqual(d.filter(function (node) { return node instanceof ConstantNode && node.value == '2' }), [c])
  })

  it('should run forEach on an ArrayNode', function () {
    // [x, 2]
    var a = new SymbolNode('x')
    var b = new ConstantNode(2)
    var c = new ArrayNode([a, b])

    var d = new ConstantNode(3)
    var nodes = []
    var paths = []
    c.forEach(function (node, path, parent) {
      nodes.push(node)
      paths.push(path)
      assert.strictEqual(parent, c)
    })

    assert.deepEqual(paths, ['items[0]', 'items[1]'])
    assert.equal(nodes.length, 2)
    assert.strictEqual(nodes[0], a)
    assert.strictEqual(nodes[1], b)
  })

  it('should map an ArrayNode', function () {
    // [x, 2]
    var a = new SymbolNode('x')
    var b = new ConstantNode(2)
    var c = new ArrayNode([a, b])

    var d = new ConstantNode(3)
    var nodes = []
    var paths = []
    var e = c.map(function (node, path, parent) {
      nodes.push(node)
      paths.push(path)
      assert.strictEqual(parent, c)

      return (node instanceof SymbolNode) && (node.name == 'x') ? d : node
    })

    assert.deepEqual(paths, ['items[0]', 'items[1]'])
    assert.equal(nodes.length, 2)
    assert.strictEqual(nodes[0], a)
    assert.strictEqual(nodes[1], b)

    assert.notStrictEqual(e, c)
    assert.deepEqual(e.items[0], d)
    assert.deepEqual(e.items[1], b)
  })

  it('should throw an error when the map callback does not return a node', function () {
    var a = new SymbolNode('x')
    var b = new ConstantNode(2)
    var c = new ArrayNode([a, b])

    assert.throws(function () {
      c.map(function () {})
    }, /Callback function must return a Node/)
  })

  it('should transform an ArrayNodes parameters', function () {
    // [x, 2]
    var a = new SymbolNode('x')
    var b = new ConstantNode(2)
    var c = new ArrayNode([a, b])

    var d = new ConstantNode(3)
    var e = c.transform(function (node) {
      return (node instanceof SymbolNode) && (node.name == 'x') ? d : node
    })

    assert.notStrictEqual(e, c)
    assert.deepEqual(e.items[0], d)
    assert.deepEqual(e.items[1], b)
  })

  it('should transform an ArrayNode itself', function () {
    // [x, 2]
    var a = new SymbolNode('x')
    var b = new ConstantNode(2)
    var c = new ArrayNode([a, b])

    var d = new ConstantNode(3)
    var e = c.transform(function (node) {
      return (node instanceof ArrayNode) ? d : node
    })

    assert.notStrictEqual(e, c)
    assert.deepEqual(e, d)
  })

  it('should traverse an ArrayNode', function () {
    var a = new ConstantNode(1)
    var b = new ConstantNode(2)
    var c = new ArrayNode([a, b])

    var count = 0
    c.traverse(function (node, path, parent) {
      count++

      switch (count) {
        case 1:
          assert.strictEqual(node, c)
          assert.strictEqual(path, null)
          assert.strictEqual(parent, null)
          break

        case 2:
          assert.strictEqual(node, a)
          assert.strictEqual(path, 'items[0]')
          assert.strictEqual(parent, c)
          break

        case 3:
          assert.strictEqual(node, b)
          assert.strictEqual(path, 'items[1]')
          assert.strictEqual(parent, c)
          break
      }
    })

    assert.equal(count, 3)
  })

  it('should clone an ArrayNode', function () {
    // [x, 2]
    var a = new SymbolNode('x')
    var b = new ConstantNode(2)
    var c = new ArrayNode([a, b])

    var d = c.clone()
    assert(d instanceof ArrayNode)
    assert.deepEqual(c, d)
    assert.notStrictEqual(c, d)
    assert.strictEqual(c.items[0], d.items[0])
    assert.strictEqual(c.items[1], d.items[1])
  })

  it('test equality with other nodes', function () {
    // [x, 2]
    var a = new SymbolNode('x')
    var b = new ConstantNode(2)
    var c = new ArrayNode([a, b])

    assert.strictEqual(c.equals(null), false)
    assert.strictEqual(c.equals(undefined), false)
    assert.strictEqual(c.equals(new ArrayNode([new SymbolNode('x'), new ConstantNode(2)])), true)
    assert.strictEqual(c.equals(new ArrayNode([new SymbolNode('x'), new ConstantNode(2), new ConstantNode(3)])), false)
    assert.strictEqual(c.equals(new ArrayNode([new SymbolNode('x'), new ConstantNode(3)])), false)
    assert.strictEqual(c.equals(new ArrayNode([new SymbolNode('x')])), false)
  })

  it('should stringify an ArrayNode', function () {
    var a = new ConstantNode(1)
    var b = new ConstantNode(2)
    var c = new ConstantNode(3)
    var d = new ConstantNode(4)
    var n = new ArrayNode([a, b, c, d])

    assert.equal(n.toString(), '[1, 2, 3, 4]')
  })

  it('should stringify an ArrayNode with custom toString', function () {
    // Also checks if the custom functions get passed on to the children
    var customFunction = function (node, options) {
      if (node.type === 'ArrayNode') {
        var string = '['
        node.items.forEach(function (item) {
          string += item.toString(options) + ', '
        })

        string += ']'
        return string
      } else if (node.type === 'ConstantNode') {
        return 'const(' + node.value + ', ' + math.typeof(node.value) + ')'
      }
    }

    var a = new ConstantNode(1)
    var b = new ConstantNode(2)

    var n = new ArrayNode([a, b])

    assert.equal(n.toString({handler: customFunction}), '[const(1, number), const(2, number), ]')
  })

  it('toJSON and fromJSON', function () {
    var b = new ConstantNode(1)
    var c = new ConstantNode(2)

    var node = new ArrayNode([b, c])

    var json = node.toJSON()

    assert.deepEqual(json, {
      mathjs: 'ArrayNode',
      items: [ b, c ]
    })

    var parsed = ArrayNode.fromJSON(json)
    assert.deepEqual(parsed, node)
  })

  it('should LaTeX an ArrayNode', function () {
    var a = new ConstantNode(1)
    var b = new ConstantNode(2)
    var c = new ConstantNode(3)
    var d = new ConstantNode(4)
    var v1 = new ArrayNode([a, b])
    var v2 = new ArrayNode([c, d])
    var n = new ArrayNode([v1, v2])

    assert.equal(n.toTex(), '\\begin{bmatrix}1&2\\\\3&4\\\\\\end{bmatrix}')
  })

  it('should LaTeX an ArrayNode with custom toTex', function () {
    // Also checks if the custom functions get passed on to the children
    var customFunction = function (node, options) {
      if (node.type === 'ArrayNode') {
        var latex = '\\left['
        node.items.forEach(function (item) {
          latex += item.toTex(options) + ', '
        })

        latex += '\\right]'
        return latex
      } else if (node.type === 'ConstantNode') {
        return 'const\\left(' + node.value + ', ' + math.typeof(node.value) + '\\right)'
      }
    }

    var a = new ConstantNode(1)
    var b = new ConstantNode(2)

    var n = new ArrayNode([a, b])

    assert.equal(n.toTex({handler: customFunction}), '\\left[const\\left(1, number\\right), const\\left(2, number\\right), \\right]')
  })
})