D3.js interview questions

D3.js uses CSS-style selectors to identify elements on which to operate.
Example:

d3.selectAll("p").style("color", "white");

d3.interpolateObject(a,b) command is used to interpolate two objects in d3.js

Mike Bostock wrote D3.js based on his work during his Ph.D. studies at the Stanford Visualization Group. Mike worked at the The New York Times for a while and is now independently working on D3.js.

D3 stands for Data-Driven Documents

A transition is a selection-like interface for animating changes to the DOM. Instead of applying changes instantaneously, transitions smoothly interpolate the DOM from its current state to the desired target state over a given duration.

To apply a transition, select elements, call selection.transition and then make the desired changes.

For example:

d3.select("body")
  .transition()
    .style("background-color", "red");

In D3.js “Enter” selection is used to create new nodes for incoming data and “Exit” selection is used eliminate outgoing nodes that are no longer required.

You can use D3 js because

• D3.js lets you to build the data visualization framework
• D3.js focuses on binding data to DOM elements.
• D3.js is written in JavaScript and uses a functional style which means you can reuse code and add specific functions to your heart’s content.