Adding operator attribute to assertion error

lib/chai/assertion.js

@@ -138,11 +138,21 @@ module.exports = function (_chai, util) {
     if (!ok) {
       msg = util.getMessage(this, arguments);
       var actual = util.getActual(this, arguments);
-      throw new AssertionError(msg, {
+      var assertionErrorObjectProperties = {
           actual: actual
         , expected: expected
         , showDiff: showDiff
-      }, (config.includeStack) ? this.assert : flag(this, 'ssfi'));
+      };
+
+      var operator = util.getOperator(this, arguments);
+      if (operator) {
+        assertionErrorObjectProperties.operator = operator;
+      }
+
+      throw new AssertionError(
+        msg,
+        assertionErrorObjectProperties,
+        (config.includeStack) ? this.assert : flag(this, 'ssfi'));
     }
   };
 

lib/chai/utils/getOperator.js

@@ -0,0 +1,55 @@
+var type = require('type-detect');
+
+var flag = require('./flag');
+
+function isObjectType(obj) {
+  var objectType = type(obj);
+  var objectTypes = ['Array', 'Object', 'function'];
+
+  return objectTypes.indexOf(objectType) !== -1;
+}
+
+/**
+ * ### .getGetOperator(message)
+ *
+ * Extract the operator from error message.
+ * Operator defined is based on below link
+ * https://nodejs.org/api/assert.html#assert_assert.
+ *
+ * Returns the `operator` or `undefined` value for an Assertion.
+ *
+ * @param {Object} object (constructed Assertion)
+ * @param {Arguments} chai.Assertion.prototype.assert arguments
+ * @namespace Utils
+ * @name getGetOperator
+ * @api public
+ */
+
+module.exports = function getOperator(obj, args) {
+  var operator = flag(obj, 'operator');
+  var negate = flag(obj, 'negate');
+  var expected = args[3];
+  var msg = negate ? args[2] : args[1];
+
+  if (operator) {
+    return operator;
+  }
+
+  if (typeof msg === 'function') msg = msg();
+
+  msg = msg || '';
+  if (!msg) {
+    return undefined;
+  }
+
+  if (/\shave\s/.test(msg)) {
+    return undefined;
+  }
+
+  var isObject = isObjectType(expected);
+  if (/\snot\s/.test(msg)) {
+    return isObject ? 'notDeepStrictEqual' : 'notStrictEqual';
+  }
+
+  return isObject ? 'deepStrictEqual' : 'strictEqual';
+};

lib/chai/utils/index.js

@@ -170,3 +170,9 @@ exports.isProxyEnabled = require('./isProxyEnabled');
  */
 
 exports.isNaN = require('./isNaN');
+
+/*!
+ * getOperator method
+ */
+
+exports.getOperator = require('./getOperator');

test/globalErr.js

@@ -43,6 +43,115 @@ describe('globalErr', function () {
     });
   });
 
+  it('should pass operator if possible during none object comparison', function () {
+    err(function () {
+      expect('cat').to.equal('dog');
+    }, {
+        message: 'expected \'cat\' to equal \'dog\''
+      , expected: 'dog'
+      , actual: 'cat'
+      , operator: 'strictEqual'
+    });
+
+    err(function () {
+      expect('cat').to.not.equal('cat');
+    }, {
+      message: 'expected \'cat\' to not equal \'cat\''
+      , expected: 'cat'
+      , actual: 'cat'
+      , operator: 'notStrictEqual'
+    });
+  });
+
+  it('should pass operator if possible during plain object comparison', function () {
+    var val1 = {
+      propVal1: 'val1'
+    };
+
+    var val2 = {
+      propVal2: 'val2'
+    };
+
+    err(function () {
+      expect(val1).to.equal(val2);
+    }, {
+        message: "expected { propVal1: 'val1' } to equal { propVal2: 'val2' }"
+      , expected: val2
+      , actual: val1
+      , operator: 'deepStrictEqual'
+    });
+
+    err(function () {
+      expect(val1).to.not.equal(val1);
+    }, {
+      message: "expected { propVal1: 'val1' } to not equal { propVal1: 'val1' }"
+      , expected: val1
+      , actual: val1
+      , operator: 'notDeepStrictEqual'
+    });
+  });
+
+  it('should pass operator if possible during function comparison', function () {
+    function f1 () {
+      this.propF1 = 'propF1';
+    }
+
+    function f2 () {
+      this.propF2 = 'propF2';
+    }
+
+    err(function () {
+      expect(f1).to.equal(f2);
+    }, {
+        message: "expected [Function: f1] to equal [Function: f2]"
+      , expected: f2
+      , actual: f1
+      , operator: 'deepStrictEqual'
+    });
+
+    err(function () {
+      expect(f1).to.not.equal(f1);
+    }, {
+      message: "expected [Function: f1] to not equal [Function: f1]"
+      , expected: f1
+      , actual: f1
+      , operator: 'notDeepStrictEqual'
+    });
+  });
+
+  it('should pass operator if possible during object comparison', function () {
+    var val1 = [
+        'string1'
+      , 'string2'
+      , 'string3'
+      , 'string4'
+    ];
+
+    var val2 = [
+      'string5'
+    , 'string6'
+    , 'string7'
+    , 'string8'
+    ];
+    err(function () {
+      expect(val1).to.equal(val2);
+    }, {
+        message: 'expected [ Array(4) ] to equal [ Array(4) ]'
+      , expected: val2
+      , actual: val1
+      , operator: 'deepStrictEqual'
+    });
+
+    err(function () {
+      expect(val1).to.not.equal(val1);
+    }, {
+      message: 'expected [ Array(4) ] to not equal [ Array(4) ]'
+      , expected: val1
+      , actual: val1
+      , operator: 'notDeepStrictEqual'
+    });
+  });
+
   it('should throw if regex val does not match error message', function () {
     err(function () {
       err(function () { throw new Err('cat') }, /dog/);

test/utilities.js

@@ -1324,4 +1324,185 @@ describe('utilities', function () {
       });
     }
   });
+
+  describe('getOperator', function() {
+    it('Must return operator if the "operator" flag is set', function() {
+      chai.use(function(_chai, _) {
+        expect(_.getOperator({}, [])).to.equal(undefined);
+        expect(_.getOperator({}, [null, null, null])).to.equal(undefined);
+
+        var obj = {};
+        _.flag(obj, 'operator', 'my-operator');
+        expect(_.getOperator(obj, [])).to.equal('my-operator');
+      });
+    });
+
+    it('Must return undefined if message is partial assertions', function() {
+      chai.use(function(_chai, _) {
+        expect(
+          _.getOperator({}, [null, 'to have the same ordered', null, 'test'])
+        ).to.equal(undefined);
+      });
+    });
+
+    it('Must return deepStrictEqual if "expected" is a object and assertion is for equal', function() {
+      chai.use(function(_chai, _) {
+        var expected = Object.create({
+          dummyProperty1: 'dummyProperty1',
+          dummyProperty2: 'dummyProperty2',
+          dummyProperty3: 'dummyProperty3'
+        });
+
+        var obj = {};
+        _.flag(obj, 'negate', false);
+
+        expect(
+          _.getOperator(obj, [
+            null,
+            'expect #{this} deep equal to #{exp}',
+            'expect #{this} not deep equal to #{exp}',
+            expected
+          ])
+        ).to.equal('deepStrictEqual');
+      });
+    });
+
+    it('Must return deepStrictEqual if "expected" is a function and assertion is for equal', function() {
+      chai.use(function(_chai, _) {
+        function expected () {
+          this.prop = 'prop';
+        }
+
+        var obj = {};
+        _.flag(obj, 'negate', false);
+
+        expect(
+          _.getOperator(obj, [
+            null,
+            'expect #{this} deep equal to #{exp}',
+            'expect #{this} not deep equal to #{exp}',
+            expected
+          ])
+        ).to.equal('deepStrictEqual');
+      });
+    });
+
+    it('Must return deepStrictEqual if "expected" is an array and assertion is for equal', function() {
+      chai.use(function(_chai, _) {
+        var expected = [
+          'item 1'
+        ];
+
+        var obj = {};
+        _.flag(obj, 'negate', false);
+
+        expect(
+          _.getOperator(obj, [
+            null,
+            'expect #{this} deep equal to #{exp}',
+            'expect #{this} not deep equal to #{exp}',
+            expected
+          ])
+        ).to.equal('deepStrictEqual');
+      });
+    });
+
+    it('Must return strictEqual if "expected" is a string and assertion is for equal', function() {
+      chai.use(function(_chai, _) {
+        var expected = 'someString';
+
+        var obj = {};
+        _.flag(obj, 'negate', false);
+
+        expect(
+          _.getOperator(obj, [
+            null,
+            'expect #{this} equal to #{exp}',
+            'expect #{this} not equal to #{exp}',
+            expected
+          ])
+        ).to.equal('strictEqual');
+      });
+    });
+
+    it('Must return notDeepStrictEqual if "expected" is a object and assertion is for inequality', function() {
+      chai.use(function(_chai, _) {
+        var expected = Object.create({
+          dummyProperty1: 'dummyProperty1',
+          dummyProperty2: 'dummyProperty2',
+          dummyProperty3: 'dummyProperty3'
+        });
+
+        var obj = {};
+        _.flag(obj, 'negate', true);
+
+        expect(
+          _.getOperator(obj, [
+            null,
+            'expect #{this} deep equal to #{exp}',
+            'expect #{this} not deep equal to #{exp}',
+            expected
+          ])
+        ).to.equal('notDeepStrictEqual');
+      });
+    });
+
+    it('Must return notDeepStrictEqual if "expected" is a function and assertion is for inequality', function() {
+      chai.use(function(_chai, _) {
+        function expected () {
+          this.prop = 'prop';
+        }
+
+        var obj = {};
+        _.flag(obj, 'negate', true);
+
+        expect(
+          _.getOperator(obj, [
+            null,
+            'expect #{this} deep equal to #{exp}',
+            'expect #{this} not deep equal to #{exp}',
+            expected
+          ])
+        ).to.equal('notDeepStrictEqual');
+      });
+    });
+
+    it('Must return notDeepStrictEqual if "expected" is an array and assertion is for inequality', function() {
+      chai.use(function(_chai, _) {
+        var expected = [
+          'item 1'
+        ];
+
+        var obj = {};
+        _.flag(obj, 'negate', true);
+
+        expect(
+          _.getOperator(obj, [
+            null,
+            'expect #{this} deep equal to #{exp}',
+            'expect #{this} not deep equal to #{exp}',
+            expected
+          ])
+        ).to.equal('notDeepStrictEqual');
+      });
+    });
+
+    it('Must return notStrictEqual if "expected" is a string and assertion is for inequality', function() {
+      chai.use(function(_chai, _) {
+        var expected = 'someString';
+
+        var obj = {};
+        _.flag(obj, 'negate', true);
+
+        expect(
+          _.getOperator(obj, [
+            null,
+            'expect #{this} equal to #{exp}',
+            'expect #{this} not equal to #{exp}',
+            expected
+          ])
+        ).to.equal('notStrictEqual');
+      });
+    });
+  });
 });