Eloquent JavaScript, 2nd Edition

Chapter 4. Data Structures: Objects and Arrays

“On two occasions I have been asked, ‘Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?’ . . . I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.”

—Charles Babbage, Passages from the Life of a Philosopher (1864)

Numbers, Booleans, and strings are the bricks that data structures are built from. But you can’t make much of a house out of a single brick. Objects allow us to group values—including other objects—together and thus build more complex structures.

The programs we have built so far have been seriously hampered by the fact that they were operating only on simple data types. This chapter ...