Foundations.Assert

Provides a set of Assert functions, for checking code pre-conditions and post-conditions.

Using Foundations.Assert

Assert and Require Versions

For each function, there are two versions. For example:

  1. Assert.assertEqual(obj1, obj2, msg, params)
  2. Assert.requireEqual(obj1, obj2, msg, params)

If the assertion evaluates to false, the "assert" function logs an error message and returns false while the "require" one throws an exception.

Messages are logged to "/var/log/messages." You can use the "tail" utility to view messages in real-time.

To monitor logged messages in real-time: 

tail -f /var/log/messages


The "-f" option causes tail to display the last 10 lines of messages
and append new lines to the display as they are added.

To show output for just your app: 

tail -f /var/log/messages | grep packageid

Note that using "tail" like this works until the log file is rotated; then you will need to reissue the command.

Using the "msg" and "params" arguments

Each function can take optional "msg" and "params" arguments. The msg parameter is used when logging an error message or throwing an error. It can also contain "#{...}" placeholders for values from the params object. For example: 

msg = "Expected a sum greater than #{count}, but it was #{amount}";

The params argument can then be used to situationally fill the placeholders. For example: 

params = {count: 3, amount: 0};

Assert Functions

Function Description
Assert.assert Logs an error if the expression is not true.
Assert.assertArray Logs an error if the expression is not an array.
Assert.assertClass Logs an error if an object does not have a given constructor.
Assert.assertDefined Logs an error if the argument is not defined.
Assert.assertEqual Logs an error if the expressions are not equal (==).
Assert.assertError Logs an error if a function does not throw the expected error.
Assert.assertFalse Logs an error if the expression is not false.
Assert.assertFunction Logs an error if the argument is not a function.
Assert.assertIdentical Logs an error if the expressions are not identical (===), that is, if they do not have the same type and value.
Assert.assertJSONObject Logs an error if the argument does not evaluate (when run through Object.prototype.toString()) to '[object Object]' or '[object Array]' (an object of an array).
Assert.assertMatch Logs an error if a regular expression pattern has no matches in a given string.
Assert.assertNumber Logs an error if the argument is not a number.
Assert.assertObject Logs an error if the argument is not an object.
Assert.assertProperty Logs an error if the object does not have a particular property or properties.
Assert.assertString Logs an error if the argument is not a string.
Assert.require Throws an error if the expression is not true
Assert.requireArray Throws an error if the expression is not an array.
Assert.requireClass Throws an error if an object does not have a given constructor.
Assert.requireDefined Throws an error if the argument is not defined.
Assert.requireEqual Throws an error if the expressions are not equal (==).
Assert.requireError Throws an error if a function does not throw the expected error.
Assert.requireFalse Throws an error if the expression is not false.
Assert.requireFunction Throws an error if the argument is not a function.
Assert.requireIdentical Throws an error if the expressions are not identical (===), that is, if they do not have the same type and value.
Assert.requireJSONObject Throws an error if the argument does not evaluate (when run through Object.prototype.toString()) to '[object Object]' or '[object Array]' (an object of an array).
Assert.requireMatch Throws an error if the pattern does not match.
Assert.requireNumber Throws an error if the argument is not a number.
Assert.requireObject Throws an error if the argument is not an object.
Assert.requireProperty Throws an error if the object does not have a particular property or properties.
Assert.requireString Throws an error if the argument is not a string.

Assert.assert

Logs an error if the expression is not true.

Syntax 

    Assert.assert(exp, msg, params);

Parameters

Argument Required Type Description
exp Yes any Expression to test
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

Returns the expression passed.

Logs an error if the expression does not evaluate to true.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var exp="";
var msg = "Does not evaluate to true";
Mojo.Log.info("assert = "+ AssertUtils.assert(exp, msg));

Example Output 

Error: Does not evaluate to true
assert = ""

Assert.assertArray

Logs an error if the expression is not an array.

Syntax 

    boolean Assert.assertArray(exp, msg, params);

Parameters

Argument Required Type Description
exp Yes any Expression to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the expression is not an array.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var ary = [{"a":"b"}];
var notAry = "this is a string";
var msg = "Not an array";
Mojo.Log.info("assert = "+ AssertUtils.assertArray(ary, msg));
Mojo.Log.info("assert = "+ AssertUtils.assertArray(notAry, msg));

Example Output 

assert = true
Error: Not an array
assert = false

Assert.assertClass

Logs an error if an object does not have a given constructor.

Syntax 

    boolean Assert.assertClass(obj, constructor, msg, params)

Parameters

Argument Required Type Description
obj Yes any Object to test for constructor.
constructor Yes any Asserted constructor.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the constructor is not the passed object's constructor.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
function cat(name) {
  this.name = name;
  this.talk = function() {
      alert( this.name + " say meeow!" );
  }
}

cat1 = new cat("felix");
Mojo.Log.info("assert = "+ AssertUtils.assertClass(cat1, cat));

Example Output 

assert = true

Assert.assertDefined

Logs an error if the argument is not defined.

Syntax 

    boolean Assert.assertDefined(exp, msg, params);

Parameters

Argument Required Type Description
exp Yes any Expression to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the argument is not defined.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var undefObj;
Mojo.Log.info("assert = "+ AssertUtils.assertDefined(undefObj, "Not defined"));

Example Output 

Error: Not defined
assert = false

Assert.assertEqual

Logs an error if the expressions are not equal (==).

Syntax 

    boolean Assert.assertEqual(exp1, exp2, msg, params);

Parameters

Argument Required Type Description
exp1 Yes any Expression to test.
exp2 Yes any Expression to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the expressions are not equal (==).

Example 

var libraries = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var str1 = "Separate but equal";
var str2 = "Separate but equal not";
Mojo.Log.info("assert = "+ AssertUtils.assertEqual(str1, str2));

Example Output 

Error: Assert.assertEqual: Separate but equal != Separate but equal not
assert = false

Assert.assertError

Logs an error if the function does not throw the expected error.

Syntax 

    boolean Assert.assertError(context, func, args, error, msg, params);

Parameters

Argument Required Type Description
context Yes any The "this" value for function. This is the first argument to an apply method. The apply() method invokes the passed function and passes context as the first parameter. The runtime uses this parameter for the this reference.
func Yes any Function to run.
args Yes any object Array of arguments. Second argument to apply() method.
error Yes any object Expected error.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the function does not throw the expected error.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var context = { errmsg1: "Err1", errmsg2: "Err2" };
var args = ["User message 1", "User message 2" ];
function f(message)
{
  throw this.errmsg1;
}

Mojo.Log.info("assert = "+ AssertUtils.assertError(context, f, args, "Err1" ));
Mojo.Log.info("assert = "+ AssertUtils.assertError(context, f, args, "UnknownErr" ));

Example Output 

assert = true
Error: Assert.assertError: error thrown was 'Err1', instead of 'UnknownErr'
assert = false

Assert.assertFalse

Logs an error if the expression is not false.

Syntax 

    boolean Assert.assertFalse(exp, msg, params);

Parameters

Argument Required Type Description
exp Yes string Expression to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the expression is not false.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var expFalse = "";
var expTrue = "something";
var msg = "Does not evaluate to false";
Mojo.Log.info("assert = "+ AssertUtils.assertFalse(expFalse, msg));
Mojo.Log.info("assert = "+ AssertUtils.assertFalse(expTrue, msg));

Example Output 

assert = true
Error: Does not evaluate to false
assert = false

Assert.assertFunction

Logs an error if the argument is not a function.

Syntax 

    boolean Assert.assertFunction(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes Function Object to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the argument is not a function.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var myFunc = new Function("5+2");
var myStr = "not a function";
var msg = "Is not a function";
Mojo.Log.info("assert = "+ AssertUtils.assertFunction(myFunc, msg));
Mojo.Log.info("assert = "+ AssertUtils.assertFunction(myStr, msg));

Example Output 

assert = true
Error: Is not a function
asset = false

Assert.assertIdentical

Logs an error if the expressions are not identical (===). Both type and value have to be the same.

Syntax 

    boolean Assert.assertIdentical(exp1, exp2, msg, params);

Parameters

Argument Required Type Description
exp1 Yes any Expression to test.
exp2 Yes any Expression to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the expressions are not identical (===).

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var a = "3";
var b =  3;
var c = "3";
var d = new String("3");

Mojo.Log.info("assert = "+ AssertUtils.assertIdentical(a,c,"Not identical"));
Mojo.Log.info("assert = "+ AssertUtils.assertIdentical(a,b,"Not identical"));
Mojo.Log.info("assert = "+ AssertUtils.assertIdentical(a,d,"Not identical"));

Example Output 

assert = true
Error: Not identical
assert = false
Error: Not identical
assert = false

Assert.assertJSONObject

Logs an error if the argument does not evaluate (when run through Object.prototype.toString()) to '[object Object]' or '[object Array]' (an object of an array).

Syntax 

    boolean Assert.assertJSONObject(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes string Object to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the argument does not evaluate to '[object Object]' or '[object Array]' (an object of an array).

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var jobj = [{ "fname": "Mabel", "lname":"Syrup", "isMember":true}];
Mojo.Log.info("assert = "+ AssertUtils.assertJSONObject(jobj, "Not an object or object in an array"));
var notObj = "Not a valid object";
Mojo.Log.info("assert = "+ AssertUtils.assertJSONObject(notObj, "Not an object or object in an array"));

Example Output 

assert = true
Error: Not an object or object in an array
assert = false

Assert.assertMatch

Logs an error if a regular expression pattern has no matches in a given string.

Syntax 

    string Assert.assertMatch(str, pattern, msg, params);

Parameters

Argument Required Type Description
str Yes string String to match against.
pattern Yes string Pattern to match (regular expression).
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

String with comma-separated matches or null.

Logs an error if the pattern does not match.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var str="The rain in SPAIN stays mainly in the plain";
var patt1=/ain/gi; // Search entire string for "ain",  ignore case
Mojo.Log.info("assert = "+ AssertUtils.assertMatch(str, patt1, "Not a match"));

Example Output 

assert = ain,AIN,ain,ain

Assert.assertNumber

Logs an error if the argument is not a number.

Syntax 

    boolean Assert.assertNumber(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes any Object to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the argument is not a number.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var num=32;
Mojo.Log.info("assert = "+ AssertUtils.assertNumber(num, "Not a number"));
var str="this is a string";
Mojo.Log.info("assert = "+ AssertUtils.assertNumber(str, "Not a number"));

Example Output 

assert = true
Error: Not a number
assert = false

Assert.assertObject

Logs an error if the argument is not an object.

Syntax 

    boolean Assert.assertObject(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes any Object to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the argument is not an object.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var txt = new String("this is an object");
Mojo.Log.info("assert = "+ AssertUtils.assertObject(txt, "Not an object"));
var str="this is not an object";
Mojo.Log.info("assert = "+ AssertUtils.assertObject(str, "Not an object"));

Example Output 

assert = true
Error: Not an object
assert = false

Assert.assertProperty

Logs an error if the object does not have a particular property or properties.

Syntax 

    boolean Assert.assertProperty(obj, props, msg, params);

Parameters

Argument Required Type Description
obj Yes any object Object to test.
props Yes any object Object containing properties to validate: {property1:value1, property2:value2}.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the object does not have a particular property or properties.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var home = new Object;
home.type= "colonial";
home.status = "foreclosed";
var props = {"status":"foreclosed"};
Mojo.Log.info("assert = "+ AssertUtils.assertProperty(home, props, "Not a property"));
props = "foreclosed";
Mojo.Log.info("assert = "+ AssertUtils.assertProperty(home, props, "Not a property"));

Example Output 

assert = true
Error: Not a property
assert = false

Assert.assertString

Logs an error if the argument is not a string.

Syntax 

    boolean Assert.assertString(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes string Object to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns 

true or false

Logs an error if the argument is not a string.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var num=32;
Mojo.Log.info("assert = "+ AssertUtils.assertString(num, "Not a string"));
var str="this is a string";
Mojo.Log.info("assert = "+ AssertUtils.assertString(str, "Not a string"));

Example Output 

Error: Not a string
assert = false
assert = true

Assert.require

Syntax 

    Assert.require(exp, msg, params);

Parameters

Argument Required Type Description
exp Yes any Expression to test.
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the expression is not true.

Example 

var exp = "";
try
{
  AssertUtils.require(exp, "Does not evaluate to true");
}
catch (err)
{
  Mojo.Log.info("Err = " + err);
}

Example Output 

Err = Error: Does not evaluate to true

Assert.requireArray

Throws an error if the expression is not an array.

Syntax 

    Assert.requireArray(exp, msg, params);

Parameters

Argument Required Type Description
exp Yes any Expression to test.
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the argument is not an array.

Example 

var libraries = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var ary = [{"a":"b"}];
var notAry = "this is a string";
var msg = "Not an array";
try
{
  AssertUtils.requireArray(ary, msg);
  Mojo.Log.info("ary is Array");
}
catch (err)
{
  Mojo.Log.info("Err = " + err); 
}
try
{
  AssertUtils.requireArray(notAry, msg);
  Mojo.Log.info("notAry is Array");
}
catch (err)
{
  Mojo.Log.info("Err = " + err);
}

Example Output 

ary is Array
Err = Error: Not an array

Assert.requireClass

Syntax 

    Assert.requireClass(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes any Object to test.
constructor Yes any Required constructor.
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the constructor is not the passed object's constructor.

Example 

var libraries = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
function cat(name) {
  this.name = name;
  this.talk = function() {
      alert( this.name + " say meeow!" );
  }
}

cat1 = new cat("felix");
try
{
  AssertUtils.requireClass(cat1, cat);
  Mojo.Log.info("cat1 has cat constructor");
}
catch (err)
{
  Mojo.Log.info("requireClass throws " + err);
}

Example Output 

cat1 has cat constructor

Assert.requireDefined

Throws an error if the passed argument is not defined.

Syntax 

    Assert.requireDefined(exp, msg, params);

Parameters

Argument Required Type Description
exp Yes any Expression to test.
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the argument is not defined.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var undefObj;
try
{
  AssertUtils.requireDefined(indefObj, "Not defined");
  Mojo.Log.info("Object is defined");
}
catch (err)
{
  Mojo.Log.info("requireDefined throws " + err);
}

Example Output 

requireDefined throws ReferenceError: indefObj is not defined

Assert.requireEqual

Throws an error if two arguments are not equal (==).

Syntax 

    Assert.requireEqual(exp1, exp2, msg, params);

Parameters

Argument Required Type Description
exp1 Yes any Expression to test.
exp2 Yes any Expression to test.
msg No string message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the expressions are not equal (==).

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var str1 = "Separate but equal";
var str2 = "Separate but equal not";
try
{
  AssertUtils.requireEqual(str1, str2, "Not equal");
  Mojo.Log.info("Objects are equal");
}
catch (err)
{
  Mojo.Log.info("requireEqual throws " + err); 
}

Example Output 

requireEqual throws Error: Not equal

Assert.requireError

Throws an error if a function does not throw an expected error.

Syntax 

    Assert.requireError(context, func, args, error, msg, params);

Parameters

Argument Required Type Description
context Yes string The "this" value for function. This is the first argument to an apply method. The apply() method invokes the passed function and passes context as the first parameter. The runtime uses this parameter for the this reference.
func Yes string Function to run.
args Yes any Array of arguments
error Yes string Expected error
msg No string message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the function does not throw an expected error.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var context = { errmsg1: "Err1", errmsg2: "Err2" };
var args = ["User message 1", "User message 2" ];
function f(message)
{
  throw this.errmsg1;
}

try
{   
  AssertUtils.requireError(context, f, args, "Err1", "Does not throw expected error");
  Mojo.Log.info("Function throws expected error");
}
catch (err)
{
  Mojo.Log.info("requireError throws " + err);
}

Example Output 

Function throws expected error

Assert.requireFalse

Throws an error if the expression does not evaluate to false.

Syntax 

    Assert.requireFalse(exp, msg, params);

Parameters

Argument Required Type Description
exp Yes any Expression to test
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the expression is not false.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var expFalse = "";
var expTrue = "something";
var msg = "Does not evaluate to false";
try
{
  AssertUtils.requireFalse(expFalse, msg);
  Mojo.Log.info("Evaluates to false");
}
catch (err)
{
  Mojo.Log.info("requireFalse throws " + err);
}
try
{
  AssertUtils.requireFalse(expTrue, msg);
  Mojo.Log.info("Evaluates to false");
}
catch (err)
{
  Mojo.Log.info("requireFalse throws " + err);
}

Example Output 

Evaluates to false
requireFalse throws Error: Does not evaluate to false

Assert.requireFunction

Syntax 

    Assert.requireFunction(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes any Object to test.
msg Yes string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params Yes any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the argument is not a function.

Example 

var libraries = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var myFunc = new Function("5+2");
var myStr = "not a function";
var msg = "Is not a function";
try
{
  AssertUtils.requireFunction(myFunc, msg);
  Mojo.Log.info("Is a function.");
}
catch (err)
{
  Mojo.Log.info("requireFunction throws " + err);
}
try
{
  AssertUtils.requireFalse(myStr, msg);
  Mojo.Log.info("Is a function.");
}
catch (err)
{
  Mojo.Log.info("requireFunction throws " + err);
}

Example Output 

Is a function.
requireFunction throws Error: Is not a function

Assert.requireIdentical

Throws an error if two expressions do not have the same value and type (===).

Syntax 

    Assert.requireIdentical(exp1, exp2, msg, params);

Parameters

Argument Required Type Description
exp1 Yes string Expression to test.
exp2 Yes string Expression to test.
msg Yes string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params Yes any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the expressions are not identical (===).

Example 

var libraries = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var a = "3";
var b =  3;
var c = "3";
var d = new String("3");

try
{
  AssertUtils.requireIdentical(a,c,"Not identical");
  Mojo.Log.info("Identical");
}
catch (err)
{
  Mojo.Log.info("requireIdentical throws " + err);
}

try
{
  AssertUtils.requireIdentical(a,b,"Not identical");
  Mojo.Log.info("Identical");
}
catch (err)
{
  Mojo.Log.info("requireIdentical throws " + err);
}

try
{
  AssertUtils.requireIdentical(a,d,"Not identical");
  Mojo.Log.info("Identical");
}
catch (err)
{
  Mojo.Log.info("requireIdentical throws " + err);
}

Example Output 

Identical
requireIdentical throws Error: Not identical
requireIdentical throws Error: Not identical

Assert.requireJSONObject

Throws an error if the passed object, when run through Object.prototype.toString(), does not evaluate to '[object Object]' or '[object Array]'.

Syntax 

    Assert.requireJSONObject(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes string Object to test.
msg No string Message to log. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the argument does not evaluate to '[object Object]' or '[object Array]' (an object of an array).

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
Mojo.Log.info("assert = "+ JSON.stringify(AssertUtils.assertJSONObject(jobj, "Not an object or object in an array")));
try
{
  AssertUtils.requireJSONObject(jobj, "Not an object or object in an array");
  Mojo.Log.info("Is an object or object in an array");
}
catch (err)
{
  Mojo.Log.info("requireJSONObject throws " + err);
}

var notObj = "Not a valid object";
try
{
  AssertUtils.requireJSONObject(notObj, "Not an object or object in an array");
  Mojo.Log.info("Is an object or object in an array");
}
catch (err)
{
  Mojo.Log.info("requireJSONObject throws " + err);
}

Example Output 

Is an object or object in an array
requireJSONObject throws Error: Not an object or object in an array

Assert.requireMatch

Throws an error if there not a match between a regular expression and a string.

Syntax 

    Assert.requireMatch(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes string Object to test.
obj Yes string Object to test.
pattern Yes string Pattern to match (regular expression).
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the pattern does not match.

Example 

var AssertUtils = libraries["foundations"].Assert;
var str = "The rain in SPAIN stays mainly in the plain";
var patt1 = /ain/gi;

//... Search entire string for "ain", ignore case
try {
  AssertUtils.requireMatch(str, patt1, "Not match");
  Mojo.Log.info("Match");
}
catch (err) {
  Mojo.Log.info("requireMatch throws " + err);
}

Example Output 

Match

Assert.requireNumber

Throws an error if the argument is not a number.

Syntax 

    Assert.requireNumber(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes any Object to test.
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the argument is not a number.

Example 

var libraries = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var num=32;
try
{
  AssertUtils.requireNumber(num, "Not a number");
  Mojo.Log.info("It is a number.");
}
catch (err)
{
  Mojo.Log.info("requireNumber throws " + err);
}
var str="this is a string";
try
{
  AssertUtils.requireNumber(str, "Not a number");
  Mojo.Log.info("It is a number.")
}
catch (err)
{
  Mojo.Log.info("requireNumber throws " + err);
}

Example Output 

It is a number.
requireNumber throws Error: Not a number

Assert.requireObject

Throws an error if a passed argument is not an object.

Syntax 

    Assert.requireObject(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes string Object to test.
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the argument is not an object.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var txt = new String("this is an object");
var str="this is not an object";

try
{
  AssertUtils.requireObject(txt, "Not an object");
  Mojo.Log.info("It is an object.");
}
catch (err)
{
  Mojo.Log.info("requireObject throws " + err);
}

try
{
  AssertUtils.requireObject(str, "Not an object");
  Mojo.Log.info("It is an object.");
}
catch (err)
{
  Mojo.Log.info("requireObject throws " + err);
}

Example Output 

It is an object.
requireObject throws Error: Not an object

Assert.requireProperty

Syntax 

    Assert.requireProperty(obj, props, msg, params);

Parameters

Argument Required Type Description
obj Yes string Object to test.
props Yes string An object containing properties to validate: {property1:value1, property2:value2}.
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the object does not have a particular property set as expected.

Example 

var libraries = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var home = new Object();
home.type= "colonial";
home.status = "foreclosed";
var props = {"status":"foreclosed"};

try
{
  AssertUtils.requireProperty(home, props, "Not a property");
  Mojo.Log.info("Property is there");
}
catch (err)
{
  Mojo.Log.info("requireProperty throws " + err);
}
props = "foreclosed";
try
{
  AssertUtils.requireProperty(home, props, "Not a property");
  Mojo.Log.info("Property is there");
}
catch (err)
{
  Mojo.Log.info("requireProperty throws " + err);
}

Example Output 

Property is there
requireProperty throws ReferenceError: props is not defined
requireProperty throws Error: Not a property

Assert.requireString

Throws an error if the argument is not a string.

Syntax 

    Assert.requireString(obj, msg, params);

Parameters

Argument Required Type Description
obj Yes string Object to test.
msg No string Message to throw. This can contain "#{...}" placeholders for values from the params object, i.e., "Expected a sum greater than #{count}, but it was #{amount}".
params No any object Parameters to fill in "msg" placeholders, i.e., {count: 3, amount: 0}.

Returns

Throws an error if the argument is not a string.

Example 

var libraries   = MojoLoader.require({ name: "foundations", version: "1.0" });
var AssertUtils = libraries["foundations"].Assert;
var num=32;
try
{
  AssertUtils.requireString(num, "Not a string");
  Mojo.Log.info("Is a string");
}
catch (err)
{
  Mojo.Log.info("requireString throws " + err);
}
var str="this is a string";
try
{
  AssertUtils.requireString(str, "Not a string");
  Mojo.Log.info("Is a string");
}
catch (err)
{
  Mojo.Log.info("requireString throws " + err);
}

Example Output 

requireString throws Error: Not a string
Is a string