assert

Logs message only when the expression is false.

Parameters	Desription
expression	Express to evaluate.
message	Message to print if express evaluates to false.

Example

var student = {
  "name": "Niki",
  "year": "Junior",
  "major": "Graphic Design"
};

console.assert(student.major === "MBA", "Major is Graphic Design");

Assertion failed: Major is Graphic Design