D3.js | d3.map.empty() Function
The map.empty() function in D3.js is used to return true if the created map containing zero entries otherwise returns false.
Syntax:
map.empty();
Parameters: This function does not accept any parameter.
Return Value: This function returns true if the map is empty otherwise returns false.
Below programs illustrate the d3.map.empty() function in D3.js:
Example 1:
<!DOCTYPE html><html> <head> <title> d3.map.empty() Function </title> </head> <body> <script> // Creating a map var map1 = d3.map({"a": 1}, {"b": 2}, {"c": 3}); var map2 = d3.map(); // Calling the map.empty() function A = map1.empty(); B = map2.empty(); // Getting the result whether the maps are empty or not console.log(A); console.log(B); </script></body> </html> |
Output:
false true
Example 2:
<!DOCTYPE html><html> <head> <title> d3.map.empty() Function </title> </head> <body> <script> // Creating a map var map1 = d3.map({"a": 1}, {"b": 2}, {"c": 3}); var map2 = d3.map({"GFG": 5}); var map3 = d3.map({}); var map4 = d3.map(); // Calling the map.empty() function A = map1.empty(); B = map2.empty(); C = map3.empty(); D = map4.empty(); // Getting the result whether // the maps are empty or not console.log(A); console.log(B); console.log(C); console.log(D); </script></body> </html> |
Output:
false false true true
Ref: https://devdocs.io/d3~5/d3-collection#map_empty
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