Chapter Seven · Behaviour
JavaScript: Working with Data
Real data comes in lists of things with named parts. This chapter builds the shapes that hold it, arrays and objects, the four methods that do most of the work with lists, JSON for data that travels, and modules that split the site's code into files.
Chapter 6 worked with one value at a time. Real pages show many things at once, and each thing has several parts: a project has a title, a description, tags and an address, and a portfolio has several projects. This chapter is about the shapes that hold data like that, and the everyday work done with them. By the end of it, the site's three projects live in a module of their own, ready for Chapter 8 to turn them into cards on the page.
Five topics. Arrays, which hold values in order, and loops, which do something with each of them. Objects, which hold values by name, and the list of objects that almost all real data looks like. Four array methods, map, filter, find and sort, and the surprises in the last of them. JSON, the text form data takes whenever it travels or is stored. And modules, which split the site's code into files with import and export, and which work only through the preview server.
Topics in This Chapter
length, push and includes, and for...of to do something with every item.?. and ??.sort.JSON.parse and JSON.stringify.export and import, loading it with type="module", and why modules need the preview server.