The **`map.containsKey()`** function in Dart is used to check if a map contains the specific key sent as a parameter. `map.containsKey()` returns `true` if the map contains that key, otherwise it returns `false`. 

Figure 1 below ﻿shows a visual representation of the `map.containsKey()` function:

# 
## Syntax
```dart
map.containsKey(key)
```

>  `map` is the name of the queue.
## Parameter
The `map.containsKey()` function requires a `key` in order to check that a specific key-value pair exists in the map.

## Return value

 The function returns a Boolean value, i.e., `true` if a specific key is present in a map or `false` if it is not present.

## Code
The following code shows how to use the `map.containsKey()` function in Dart:


import 'dart:convert';

void main() {
  var map = new Map();

  map [1] = 'Tom';
  map [2] = 'Alsvin';
  map [3] = 'Eddie';
  //map containg 3 key
  print("map contains key number 3: ${map.containsKey(3)}");

  //map containg 0 key
  print("map contains key number 0: ${map.containsKey(0)}");
}

What is the map.containsKey() method in Dart?

map.containsKey() in Dart verifies the presence of a specific key in a map, returning true or false.