不使用关系运算符的 JavaScript 条件表达式

Question

Here is the prompt to start.

This is one way to code a conditional expression that tests whether a Boolean variable named isValid is true:

isValid == true

Code another way that doesnt require the use of a relational operator.

How do you evaluate a boolean to be true without a relational operator? Has me a bit stuck

Answer 1

Javascripts relational operators are :

• Greater than operator ( > )
• Greater than or equal operator ( >= )
• Less than operator ( < )
• Less than or equal operator ( <= )
• The equality operators ( == / === ) (and the inequality operators ( !== )

One simple way to evaluate a variable as true or false based on it's "truthiness", without using relational operators, would be to use the ! (not) operator twice

!!isValid

As "not thruthy" evaluates to false , and reverting it again as "not false" evaluates to true .

Answer 2

Just use the expression by itself in any context that treats it as a boolean. For instance.

if (isValid) {
    ...
}

or

someVar = isValid ? "truevalue" : "falsevalue";