console comes with the
console.assert method, which is pretty useful to write some tests in your code.
This method has the syntax of:
console.assert(assertion: bool, msg: string, obj1: any, obj2: any,...)
assertion expression returns
false, the execution will be stopped, and the
msg string will be printed out after the
"Assertion failed:" message. You can format the
msg just like how you format strings in languages like C++, using any
obj followed after
Otherwise, the execution continues.
const actual = 10; const expected = 15; console.assert(actual === expected, "Expected %d. Got %d", expected, actual); console.log("All good!);
Assertion failed: Expected 15. Got 10
If we change
actual = 15, the output on the screen will be: