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>
</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>
</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> |
Output:
0 undefined
Ref: https://devdocs.io/d3~5/d3-collection#map_clear