Null safety in dart

Nil from backend developer to irritated frontend developer

Okay sometime we itself create some nil, not only from backend

Why Null safety ?

sometime while loading nil or null data in app, App will crash. To avoid it null safety is important

so in this blog we will discuss about null safety in flutter

When will null affect the code

int? a;
print(a); // null

above code will not create any error. But below code will.

// (Note this code will not run)
int? a;
int? b = 2;
print(b); // 2
print(a); // null
print(a + b); // error 

So when we trying to do something with null our code will crash

Null safety in flutter

Null safety can done in more ways

• With if condition
• Assertion operator(!)
• if null operator (??)

With if condition

its like avoiding the line with if condition

int? a;
int? b = 2;
if (a == null) {
  print("a is null"); // a is null
} else {
  print(a + b);
}

this is one type of avoiding null. But free advise don’t do with this type

Assertion operator(!)

use ! when you sure value is not null

Example

int? a;
  int? b = 2;
  if (b == 2) {
    a = 2;
  }
  print(a! + b);

Here we assigned a = 2 so we can use ! . If not code will crash

int? a;
int? b = 2;
if (b != 2) {
  a = 2;
}
print(a! + b); // code will crash here

(Note: use this when your sure that value is not null)

If null operator (??)

one of the safest way to handle null safety.

Here will assign any default value, if the value is null

Example

int? a;
int? b = 2;
print((a ?? 0 ) + b); // 2

Here the operator will check for null, If it is null, it will assign 0 (as i assigned 0 as default)

a is variable. ?? if for checking value. 0 The default value you want

Free advice use this method for your null safety

int? a;
int? b = 2;
a ??= 0;
print(a + b); // 2

we can also handle like a ??= 0 . This method is like checking and assigning using ternary operator.

Same like for other data type to.

If any mistake or you need to shout me, comments session in always opened

நன்றி வணக்கம் || Thank you