stringify_test.js

var Sinon = require("sinon")
var stringify = require("..")
function jsonify(obj) { return JSON.stringify(obj, null, 2) }

describe("Stringify", function() {
  it("must stringify circular objects", function() {
    var obj = {name: "Alice"}
    obj.self = obj
    var json = stringify(obj, null, 2)
    json.must.eql(jsonify({name: "Alice", self: "[Circular ~]"}))
  })

  it("must stringify circular objects with intermediaries", function() {
    var obj = {name: "Alice"}
    obj.identity = {self: obj}
    var json = stringify(obj, null, 2)
    json.must.eql(jsonify({name: "Alice", identity: {self: "[Circular ~]"}}))
  })

  it("must stringify circular objects deeper", function() {
    var obj = {name: "Alice", child: {name: "Bob"}}
    obj.child.self = obj.child

    stringify(obj, null, 2).must.eql(jsonify({
      name: "Alice",
      child: {name: "Bob", self: "[Circular ~.child]"}
    }))
  })

  it("must stringify circular objects deeper with intermediaries", function() {
    var obj = {name: "Alice", child: {name: "Bob"}}
    obj.child.identity = {self: obj.child}

    stringify(obj, null, 2).must.eql(jsonify({
      name: "Alice",
      child: {name: "Bob", identity: {self: "[Circular ~.child]"}}
    }))
  })

  it("must stringify circular objects in an array", function() {
    var obj = {name: "Alice"}
    obj.self = [obj, obj]

    stringify(obj, null, 2).must.eql(jsonify({
      name: "Alice", self: ["[Circular ~]", "[Circular ~]"]
    }))
  })

  it("must stringify circular objects deeper in an array", function() {
    var obj = {name: "Alice", children: [{name: "Bob"}, {name: "Eve"}]}
    obj.children[0].self = obj.children[0]
    obj.children[1].self = obj.children[1]

    stringify(obj, null, 2).must.eql(jsonify({
      name: "Alice",
      children: [
        {name: "Bob", self: "[Circular ~.children.0]"},
        {name: "Eve", self: "[Circular ~.children.1]"}
      ]
    }))
  })

  it("must stringify circular arrays", function() {
    var obj = []
    obj.push(obj)
    obj.push(obj)
    var json = stringify(obj, null, 2)
    json.must.eql(jsonify(["[Circular ~]", "[Circular ~]"]))
  })

  it("must stringify circular arrays with intermediaries", function() {
    var obj = []
    obj.push({name: "Alice", self: obj})
    obj.push({name: "Bob", self: obj})

    stringify(obj, null, 2).must.eql(jsonify([
      {name: "Alice", self: "[Circular ~]"},
      {name: "Bob", self: "[Circular ~]"}
    ]))
  })

  it("must stringify repeated objects in objects", function() {
    var obj = {}
    var alice = {name: "Alice"}
    obj.alice1 = alice
    obj.alice2 = alice

    stringify(obj, null, 2).must.eql(jsonify({
      alice1: {name: "Alice"},
      alice2: {name: "Alice"}
    }))
  })

  it("must stringify repeated objects in arrays", function() {
    var alice = {name: "Alice"}
    var obj = [alice, alice]
    var json = stringify(obj, null, 2)
    json.must.eql(jsonify([{name: "Alice"}, {name: "Alice"}]))
  })

  it("must call given decycler and use its output", function() {
    var obj = {}
    obj.a = obj
    obj.b = obj

    var decycle = Sinon.spy(function() { return decycle.callCount })
    var json = stringify(obj, null, 2, decycle)
    json.must.eql(jsonify({a: 1, b: 2}, null, 2))

    decycle.callCount.must.equal(2)
    decycle.thisValues[0].must.equal(obj)
    decycle.args[0][0].must.equal("a")
    decycle.args[0][1].must.equal(obj)
    decycle.thisValues[1].must.equal(obj)
    decycle.args[1][0].must.equal("b")
    decycle.args[1][1].must.equal(obj)
  })

  it("must call replacer and use its output", function() {
    var obj = {name: "Alice", child: {name: "Bob"}}

    var replacer = Sinon.spy(bangString)
    var json = stringify(obj, replacer, 2)
    json.must.eql(jsonify({name: "Alice!", child: {name: "Bob!"}}))

    replacer.callCount.must.equal(4)
    replacer.args[0][0].must.equal("")
    replacer.args[0][1].must.equal(obj)
    replacer.thisValues[1].must.equal(obj)
    replacer.args[1][0].must.equal("name")
    replacer.args[1][1].must.equal("Alice")
    replacer.thisValues[2].must.equal(obj)
    replacer.args[2][0].must.equal("child")
    replacer.args[2][1].must.equal(obj.child)
    replacer.thisValues[3].must.equal(obj.child)
    replacer.args[3][0].must.equal("name")
    replacer.args[3][1].must.equal("Bob")
  })

  it("must call replacer after describing circular references", function() {
    var obj = {name: "Alice"}
    obj.self = obj

    var replacer = Sinon.spy(bangString)
    var json = stringify(obj, replacer, 2)
    json.must.eql(jsonify({name: "Alice!", self: "[Circular ~]!"}))

    replacer.callCount.must.equal(3)
    replacer.args[0][0].must.equal("")
    replacer.args[0][1].must.equal(obj)
    replacer.thisValues[1].must.equal(obj)
    replacer.args[1][0].must.equal("name")
    replacer.args[1][1].must.equal("Alice")
    replacer.thisValues[2].must.equal(obj)
    replacer.args[2][0].must.equal("self")
    replacer.args[2][1].must.equal("[Circular ~]")
  })

  it("must call given decycler and use its output for nested objects",
    function() {
    var obj = {}
    obj.a = obj
    obj.b = {self: obj}

    var decycle = Sinon.spy(function() { return decycle.callCount })
    var json = stringify(obj, null, 2, decycle)
    json.must.eql(jsonify({a: 1, b: {self: 2}}))

    decycle.callCount.must.equal(2)
    decycle.args[0][0].must.equal("a")
    decycle.args[0][1].must.equal(obj)
    decycle.args[1][0].must.equal("self")
    decycle.args[1][1].must.equal(obj)
  })

  it("must use decycler's output when it returned null", function() {
    var obj = {a: "b"}
    obj.self = obj
    obj.selves = [obj, obj]

    function decycle() { return null }
    stringify(obj, null, 2, decycle).must.eql(jsonify({
      a: "b",
      self: null,
      selves: [null, null]
    }))
  })

  it("must use decycler's output when it returned undefined", function() {
    var obj = {a: "b"}
    obj.self = obj
    obj.selves = [obj, obj]

    function decycle() {}
    stringify(obj, null, 2, decycle).must.eql(jsonify({
      a: "b",
      selves: [null, null]
    }))
  })

  it("must throw given a decycler that returns a cycle", function() {
    var obj = {}
    obj.self = obj
    var err
    function identity(key, value) { return value }
    try { stringify(obj, null, 2, identity) } catch (ex) { err = ex }
    err.must.be.an.instanceof(TypeError)
  })

  describe(".getSerialize", function() {
    it("must stringify circular objects", function() {
      var obj = {a: "b"}
      obj.circularRef = obj
      obj.list = [obj, obj]

      var json = JSON.stringify(obj, stringify.getSerialize(), 2)
      json.must.eql(jsonify({
        "a": "b",
        "circularRef": "[Circular ~]",
        "list": ["[Circular ~]", "[Circular ~]"]
      }))
    })

    // This is the behavior as of Mar 3, 2015.
    // The serializer function keeps state inside the returned function and
    // so far I'm not sure how to not do that. JSON.stringify's replacer is not
    // called _after_ serialization.
    xit("must return a function that could be called twice", function() {
      var obj = {name: "Alice"}
      obj.self = obj

      var json
      var serializer = stringify.getSerialize()

      json = JSON.stringify(obj, serializer, 2)
      json.must.eql(jsonify({name: "Alice", self: "[Circular ~]"}))

      json = JSON.stringify(obj, serializer, 2)
      json.must.eql(jsonify({name: "Alice", self: "[Circular ~]"}))
    })
  })
})

function bangString(key, value) {
  return typeof value == "string" ? value + "!" : value
}