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Control Flow

Control flow statements allow you to control the execution order of your code.

Boolean convertible types​

The following types can be used as a condition

Always false

false when 0

⚠️ Any other type will throw a runtime error!

Conditional Statements​

if Statement​

The if statement executes a block of code if the specified condition is true.

if (condition) {
  // Block of code
}

else Statement​

The else statement executes a block of code if the condition in the if statement is false.

if (condition) {
  // Block of code if condition is true
} else {
  // Block of code if condition is false
}

else if Statement​

The else if statement is used to specify multiple conditions.

if (condition1) {
  // Block of code if condition1 is true
} else if (condition2) {
  // Block of code if condition2 is true
} else {
  // Block of code if no conditions are true
}

Loops​

for Loop​

The for loop repeats a block of code a specific number of times, based on the condition provided.

for (let i = 0; i < 10; i++) {
  // Block of code to repeat
}

ranged-for​

The ranged-for loop iterates over an iterable type (string, array)

const arr = [1,2,3];
for(const element : arr) {
    //repeat 3 times
}

while Loop​

The while loop executes a block of code as long as the specified condition is true.

while (condition) {
  // Block of code to repeat
}

repeat Loop​

The repeat loop executes a block of code forever.

repeat {
  // Block of code to repeat
}

repeat...while Loop​

The repeat...while loop executes a block of code once, and then repeats it as long as the specified condition is true.

repeat {
  // Block of code to repeat
} while(condition);

match Statement​

The match statement provides conditional branching similar to switch in other languages, but with clearer and safer semantics:

  • No fallthrough: Only one matching case is executed.
  • Scoped cases: Each case introduces a new block scope.
  • Optional default: Runs when no other case matches.
match (expression) {
  case value1:
    // code for value1

  case value2:
    // code for value2

  default:
    // code if no case matches
}
  • Values are compared using strict equality (===).
  • Each case block is isolated; variables declared inside do not leak outside.

Control Flow with break and continue​

break​

The break statement exits a loop or switch statement early, skipping any remaining iterations.

for (let i = 0; i < 10; i++) {
  if (i === 5) {
    break;  // Exits the loop when i equals 5
  }
  console.log(i);
}

continue​

The continue statement skips the current iteration of a loop and proceeds to the next iteration.

for (let i = 0; i < 10; i++) {
  if (i === 5) {
    continue;  // Skips the iteration when i equals 5
  }
  console.log(i);
}

Conditional Shortcuts​

Varjus supports conditional shortcut evaluation with logical operators.

  • || (OR): If the left-hand side is truthy, the right-hand side is not evaluated.
  • && (AND): If the left-hand side is falsy, the right-hand side is not evaluated.
const a = true || someFunction();  // someFunction is not called
const b = false && otherFunction(); // otherFunction is not called

This behavior can be useful for fallback values or guarding expressions.