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An if statement is used to make the program take a route, or another, depending on the result of an expression evaluation.
This is the simplest example, which always executes:
if (true) {
//do something
}
on the contrary, this is never executed:
if (false) {
//do something (? never ?)
}
If you have a single statement to execute after the conditionals, you can omit the block, and just write the statement:
if (true) doSomething()
The conditional checks the expression you pass to it for true or false value. If you pass a number, that always evaluates to true unless it’s 0. If you pass a string, it always evaluates to true unless it’s an empty string. Those are general rules of casting types to a boolean.
Else
You can provide a second part to the if statement: else.
You attach a statement that is going to be executed if the if condition is false:
if (true) {
//do something
} else {
//do something else
}
Since else accepts a statement, you can nest another if/else statement inside it:
if (a === true) {
//do something
} else if (b === true) {
//do something else
} else {
//fallback
}