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JavaScript D3.js Data Binding with D3.js Data Binding

Dakota Sexton
Dakota Sexton
1,077 Points

I'm confused. Huston types 'circles', not 'circle', into the console. Shouldn't 'circle' always remain singular?

In the data binding lesson, Huston talks about creating an svg circle for every data point in the databinding.html doc. However, when he demonstrates how to double-check the data in the javascript console, he very explicitly types 'circles.' Am I missing something? Shouldn't 'circle' always be singular?

2 Answers

Steven Parker
Steven Parker
229,968 Points

He explains this is known as a "ghost selection" which is empty since there are (initially) no elements of that type. While his use of "circles" may have been accidental, if I understand what is happening he could potentially use ANY identifier that does not already exist.

Stephen Emery
Stephen Emery
14,384 Points

You are right, the code he writes will fail. If you run 'viz.selectAll('circle') you will see the array he's talking about.