Dart Cheat Sheet

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Dart Cheat Sheet

What`s inside

A complete Dart cheat sheet for everyday use.
(from beginners to advanced users).

About the Content

If you are not an every day Dart person…. or
If you forgot a syntax that you once knew … or
If you want to take a glimpse of how things are done in Dart … or

I think that is too many or’s already.

Dart Cheat Sheet

Introduction

  • ⇒ Made by Google
  • ⇒ Object Oriented
  • ⇒ Single Threaded
  • ⇒ Open Source
  • ⇒ Dart Native for mobile, command-line, server-side
  • ⇒ Dart Web for web apps

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  • ⇒ Type System
  • ⇒ Classes (Single inheritance)
  • ⇒ Interfaces (Multiple interfaces)
  • ⇒ Concurrency (with isolates)
  • ⇒ Collections (Heterogeneous by default)
  • ⇒ Generics
  • ⇒ Optional Typing
  • ⇒ Async Await
  • ⇒ Productive development (Hot reloading)

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Tools

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Compilers

  • ⇒ dart2aot, dart to native x64 machine code
  • ⇒ dartdevc (development time compiler), used only for web dev
  • ⇒ dart2js (production time compiler), dart to javascript

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Command Line

helloWorld.dart main() { print(“Hello World !!”); } . Terminal dart helloWorld.dart
> Hello World !! .
Get all dependent packages. pub get . Upgrade packages to newer version. pub upgrade . Build the application pub build . Get commandline help pub help .

Data Manipulation

Type Conversion

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Definite Loop

for loop

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Definite Loop

for-in loop

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Indefinite Loop

while loop

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Indefinite Loop

do-while loop

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break statement: Take the control out of a construct

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continue statement: Skip a statement in the iteration

Label with Break . Label with Continue .
if statement . If…Else statement . else…if ladder . switch…case statement .

Functions

Functions in Dart .
To specify optional positional parameters, use square [] brackets. .
The parameter’s name must be specified while the value is being passed. Curly brace {} can be used to specify optional named parameters. .
Assigning parameter values by default. .
A concise mechanism to represent functions. .

Classes & Objects

Class declarations are themselves interfaces in Dart. .
A class in terms of OOP is a blueprint for creating objects. It encapsulates data for the object. .

Class Inheritance lets us create new classes (child/sub classes) from an existing class (base/parent/super class).

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Normal Constructor . Named Constructor . Factory Constructor .

Variables And Data Types

Indentifiers & Operators

Identifiers are names given to elements in a program like variables, functions etc.

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Arithmetic Operators .
Equality And Relational Operator .
Assignment Operators .
Logical Operators .
Bitwise and Shift Operators .
Every time a function is called, a reference to the object is required. The Cascade Operator can be used as a shorthand in cases where a sequence of invocations are required. .
Spread Operator . More On Spread Operators

Variables And Data Types

Data Types

Everything you can place in a variable is an Object. Numbers, functions, and null are all objects. .

Numbers in Dart

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String is a sequence of UTF-16 code units

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Booleans in Dart

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– A rune is simply an integer representing the Unicode code point.

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Enums are used for defining named constant values

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Collection

In Dart, Array is represented in the form of a List

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A Map is a dynamic collection of key value pairs.

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A collection of objects in which each object can occur only once. .
A hash table based implementation of Map. .
An unordered hash-table based Set implementation. .
A collection that can be manipulated at both ends.

Useful for first-in, first-out collection

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More

If you never intend to change a variable, use final or const.
– final variable can be set only once
– const variable is a compile-time constant (implicit final)

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Enforces a restriction on the data type of the values that can be contained by the collection. .

Dart built-int exceptions:

⇒ IntegerDivisionByZeroException: When a number is divided by zero.

⇒ IOException: Base class for all Inupt-Output related exceptions.

⇒ DeferredLoadException : Thrown when a deferred library fails to load.

⇒ FormatException: Thrown when a string or some other data does not have an expected format and cannot be parsed or processed

⇒ IsolateSpawnException: Thrown when an isolate cannot be created.

⇒ Timeout: Thrown when a scheduled timeout happens while waiting for an async result

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A function-type alias which can be used as pointer to specify a function signature that we want specific functions to match.

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A means for getting a value sometime in the future.

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