Arrow Function in Dart

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Arrow Function In Dart

Dart has a special syntax for the function body, which is only one line. The arrow function is represented by => symbol. It is a shorthand syntax for any function that has only one expression.

Syntax

The syntax for the dart arrow function.

returnType functionName(parameters...) => expression;
Info

Note: The arrow function is used to make your code short.=> expr syntax is a shorthand for { return expr; }.

Example 1: Simple Interest Without Arrow Function

This program finds simple interest without using the arrow function.

// function that calculate interest
double calculateInterest(double principal, double rate, double time) {
  double interest = principal * rate * time / 100;
  return interest;
}

void main() {
  double principal = 5000;
  double time = 3;
  double rate = 3;

  double result = calculateInterest(principal, rate, time);
  print("The simple interest is $result.");
}

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Example 2: Simple Interest With Arrow Function

This program finds simple interest using the arrow function.

// arrow function that calculate interest
double calculateInterest(double principal, double rate, double time) =>
    principal * rate * time / 100;

void main() {
  double principal = 5000;
  double time = 3;
  double rate = 3;

  double result = calculateInterest(principal, rate, time);
  print("The simple interest is $result.");
}

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Example 3: Simple Calculation Using Arrow Function

This program finds the sum, difference, multiplication, and division of two numbers using the arrow function.

int add(int n1, int n2) => n1 + n2;
int sub(int n1, int n2) => n1 - n2;
int mul(int n1, int n2) => n1 * n2;
double div(int n1, int n2) => n1 / n2;

void main() {
  int num1 = 100;
  int num2 = 30;

  print("The sum is ${add(num1, num2)}");
  print("The diff is ${sub(num1, num2)}");
  print("The mul is ${mul(num1, num2)}");
  print("The div is ${div(num1, num2)}");
}

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Video

Watch our video on arrow functions in Dart.

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