The stack.keys() method makes an array of strings as an argument and returns the stack generator.
Syntax:
stack.keys([keys])
Parameters: This method accepts a single parameter as mentioned above and described below.
- domain: This parameter holds an array of strings as key arguments.
Return Value: This method returns the stack generator.
Example:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src=
"https://d3js.org/d3.v5.min.js">
</script>
</head>
<body>
<h1 style="text-align: center; color: green;">
GeeksforGeeks
</h1>
<center>
<canvas id="gfg" width="200" height="200">
</canvas>
</center>
<script>
var data = [
{a: 3840, b: 1920, c: 960, d: 400},
{a: 1600, b: 1440, c: 960, d: 400},
{a: 640, b: 960, c: 640, d: 400},
{a: 320, b: 480, c: 640, d: 400}
];
var stackGen = d3.stack()
// Defining keys
.keys(["a", "b", "c", "d"])
var stack = stackGen(data);
console.log(stack);
for (i = 0; i < 4; i++) {
// Displaying keys
console.log(stack[i].key);
}
</script>
</body>
</html>
Output:
