D3.js | d3.map.clear() Function

Last Updated : 28 Jun, 2019

The map.clear() function in D3.js used to remove all the entries from the created map.

Syntax:

d3.map.clear();

Parameters: This function does not accept any parameter.

Return Value: This function does not return any values.

Below programs illustrate the d3.map.clear() function in D3.js:

Example 1:

<!DOCTYPE html> 
<html> 
    
<head> 
    <title> d3.map.clear() Function</title> 
    
    <script src='https://d3js.org/d3.v4.min.js'></script> 
</head> 
  
<body> 
  <script> 
       
     // Creating a map 
     var map = d3.map({"a": 1}, {"b": 2}, {"c": 3}); 
   
     // Calling the map.clear() function 
     map.clear(); 
        
     // Checking whether the value for the specified key  
     // is present or not 
     A = map.get("a"); 
        
    // Getting the output either value of the specified key 
    // string or undefined if the key is not present 
    console.log(A); 
       
  </script> 
</body> 
  
</html> 

Output:

undefined

Example 2:

<!DOCTYPE html> 
<html> 
    
<head> 
    <title> d3.map.clear() Function</title> 
    
    <script src='https://d3js.org/d3.v4.min.js'></script> 
</head> 
  
<body> 
  <script> 
       
     // Constructing a map 
     var map = d3.map({"a": 0}, {"b": 1}, {"c": 2}); 
        
     // Checking whether the value for the specified key 
     // is present or not before calling clear() function 
     A = map.get("a"); 
        
     // Getting the output of value 
     console.log(A); 
       
     // Calling the map.clear() function 
     map.clear(); 
       
     // Checking whether the value for the specified key 
     // is present or not after calling clear() function 
     B = map.get("a"); 
        
     // Getting the output of value 
     console.log(B); 
  </script> 
</body> 
  
</html> 