Booleans, Logic & Comparators
In JavaScript, there are 18014398509481983 integer values, a near infinite amount of floats (decimals) and strings, but only 2 boolean values: true and false.
This makes them super useful for decision making - on occasions you will want your code to do one thing given one set of conditions, and another thing given a different set of conditions. That kind of logic is made possible by booleans.
The most common way to use a boolean in your code is not by using the literal true or false values, but by using comparison operators.
These compare two other values - for example two numbers - and tell you whether a particular relationship exists between those values.
For example, the statement 1 > 0 evaluates to true, and the statement 1 < 0 evaluates to false.
Building on this, you can assert things about combinations of booleans, to check if both or either of the values are true or false. This is done using logical operators.
Truthiness
Another important concept related to booleans is truthiness.
Every value in JavaScript is either truthy or falsy.
There are only a few falsy values:
false''- an empty string0nullundefinedNaN- not a number (e.g an invalid mathematical operation such as the result of dividing by zero)
Anything else is a truthy value.
The idea here is to allow you to avoid making assertions like:
or
Truthiness allows both of the above to be written as:
To run the tests for this challenge, run npm test -- booleans.
In the same manner as before, try to fix all of the failing tests.
- Run the tests
- Read the error message
- Write some code to fix that message
- Repeat
And again, commit to git and push to Github regularly, and use the links provided and google to help you if you get stuck!
Once done, you can move onto the next challenge.