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Top 7 Dart tips and tricks for cleaner Flutter apps
5 min read
Mar 05, 2025
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Dart is a client-optimized programming language for quickly building mobile, desktop, and server apps. Google developed it to be used with its cross-platform Flutter framework. With Flutter and Dart, you can build apps with a slick UI and a native feel.
This blog will provide you with the top 7 Dart tips to help you improve your app development. You can use these tips to write concise code and take advantage of Dart’s many features.
Tips and tricks at a glance#
Use anonymous functions as arguments.
Make Dart classes callable with the
callmethod.Use
.entriesto iterate through a map.Use getters and setters to provide controlled access to your data.
Use Dart sets for managing collections of unique items.
Utilize Flutter’s inspect widget for better UI debugging.
Use sync and async generators.
Use anonymous functions as arguments#
In the Dart language, functions can be passed as arguments to other functions. Dart provides anonymous functions that do not need a name and can be used directly. To learn more about Dart, you can look at the course Developing Web Applications with Dart.
Below is an example of an anonymous function in Dart. Here, we pass an anonymous cube function to a built-in method, forEach, to get the cube for every item in a list.
main() {var list = [1,2,3];list.forEach((item) {print(item*item*item);});}
We can also pass anonymous functions as arguments to other functions. This approach to your code is useful when you use functional operators (like map, reduce, or where).
Below is an example of defining and assigning an anonymous function to a variable.
void main() {final sayHello = (name) => 'Hey, $name';intro(sayHello, 'Amanda');}void intro(String Function(String) greet,String name) {print(greet(name));print('Build cool Flutter apps');}
sayHello is passed to the intro function, which takes the Function argument. On line 6, String Function(String) is a function type that returns a string from a given string argument. Our anonymous function has the same signature, which is passed as an argument.
Make Dart classes callable with the call method#
With Dart, you can create a callable class that allows that class instance to be called as a function. We do this with the call() method. See the syntax below:
class class_name {... // Classreturn_type call ( parameters ) {... // Call the function content}}
Let’s see this in action with an example.
class EducativeIntro {// Defining the call methodString call(String a, String b, String c) => 'Welcome to $a$b$c';}// Main functionvoid main() {var educative_input = EducativeIntro();// Calling the class through its instancevar educative_output = educative_input('our ', 'Dart ', 'tutorial');print(educative_output);}
Note: Dart doesn’t support multiple callable methods.
Use .entries to iterate through a map#
In Dart, can you iterate through a map in a null-safe manner using entries? Say we have a map that tracks the amount spent on different products. Typically, we’d iterate through this map with the ! operator.
void main() {// Sample mapvar moneySpent = {'Food': 150,'Transport': 50,'Entertainment': 100};// Iterating over keysfor (var key in moneySpent.keys) {// Using a null-aware operator to handle potential null valuesfinal value = moneySpent[key] ?? 'No value';print('$key: $value');}}
We can improve this code by using a loop and making it more null-safe. When we iterate with the entires variable, we can access our key-value pairs in a null-safe manner.
void main() {// Sample mapvar moneySpent = {'Food': 150,'Transport': 50,'Entertainment': 100};// Iterating over entries (key-value pairs)for (var entry in moneySpent.entries) {// Safely accessing keys and valuesprint('${entry.key}: ${entry.value}');}}
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Use getters and setters to provide controlled access to your data#
Getters and setters are special methods that provide read and write access to an object’s properties. Getters and setters are similar to instance variables: a dot operator (.) is simply followed by the function name.
Getters are functions that retrieve the values of an object’s properties. We use the get keyword.
Below is an example where we create a getter function on line 13 that will return the value of the current instance’s name. On line 21, we call the getter function, and the output should display Sarah.
class Person{String name;String gender;int age;Person(this.name, this.gender, this.age);Person.newBorn(){this.age = 0;}// Getter function getting the value of a nameString get personName => name;walking() => print('$name is walking');talking() => print('$name is talking');}int main() {var firstPerson = Person("Sarah","Female",25);print(firstPerson.personName);}
Setters are functions used to write the values of an object’s properties. We use the set keyword.
class Person{String name;String gender;int age;String get personName => name;// Setter function for setting the value of agevoid set personAge(num val){if(val < 0){print("Age cannot be negative");} else {this.age = val;}}walking() => print('$name is walking');talking() => print('$name is talking');}int main() {var firstPerson = Person();firstPerson.personAge = -5;print(firstPerson.age);}
On lines 9–15, we create a setter function that sets the value for age. We also give it a condition so we cannot input a negative age. On line 23, we set the age value for firstPerson using the personAge setter function.
Use Dart sets for managing collections of unique items#
A list is one of Dart’s most common collection types, but lists can hold duplicate items. Sometimes, we want only a collection of unique values. This is where a Set is useful.
final countriesSet = {'USA','India','Iceland','USA',};
Two elements cannot be equal in a set, so the code above will offer a warning and not compile. This is also true if we use a const set.
Utilize Flutter’s inspect widget for better UI debugging#
In web development, the inspect element commonly tells you all the properties applied to an HTML tag. Dart provides a similar feature called the Inspect Widget that can make app development with Flutter easier. The Flutter Widget Inspector can locate any widget on the screen and view its properties.
The inspector can also help you visualize Flutter widget trees to understand layouts or identify layout issues.
To use it, follow the steps below:
Click the “Flutter inspector” button.
Click the “Enable Select Widget Mode” button.
Select a widget on the screen to get more information on it.
Source: Flutter documentation
Use sync and async generators#
In Dart, generators make it possible to produce a sequence of values. There are two generator functions:
Synchronous generator: Returns an iterable object
Asynchronous generator: Returns a Stream object
In other words, the synchronous generator returns a collection of values that can be accessed sequentially. We do this by marking the function body as sync*. Then, we use yield statements for the values.
void main() {// Call the count function with a specified valuevar numbers = count(5);// Iterate over the generated numbers and print eachfor (var number in numbers) {print(number);}}Iterable<int> count(int n) sync* {for (var i = 1; i <= n; i++) {yield i;}}
The asynchronous generator, on the other hand, returns a Stream object. A Stream allows us to receive a sequence of events. We do this by marking the function body as async*. Then, we use yield statements for the values.
void main() async {// Call the countStream function with a specified valuevar stream = countStream(5);// Use await for to iterate over the streamed valuesawait for (var number in stream) {print(number);}}Stream<int> countStream(int n) async* {for (var i = 1; i <= n; i++) {yield i;}}
Recap and next steps#
We hope these tips help you make the most of Dart and all the features it offers. Flutter and Dart are a powerful pair for building apps that feel native and slick. Other advanced Dart tools to investigate next are:
Spread operators for nested if-statements
Named constructors and initializer lists
Dart libraries
Enumerated types
Check out the Educative course Developing Web Applications with Dart to get hands-on practice with Dart and learn its new features. You will dive deep into Dart 2 language features and become confident with Dart extensions, enums, mixins, generics, libraries, and more.
Happy learning!
Continue learning about Dart and app development#
Frequently Asked Questions
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What are the best libraries for Dart app development?
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What real-world applications are built using Dart and Flutter?
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What resources can help me learn Dart and Flutter together?
Written By:
Tehreem Arshad
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