JavaScript lesson 21: Arrays of objects

What your child will learn

Learning goal: store a list of things as an array of objects.

Success looks like

• I can store a list of things as an array of objects.
• I can loop through it and use each object's properties.
• I can find, total and add records.

Key words

array of objects · record · property · loop · data

What to have ready

• A device with a web browser (the code runs in the browser – nothing to install)
• Paper for tracing
• A keyboard helps for typing code (a tablet or phone works too)

The big ideas (for the adult)

A list of things with details is an array of objects: [{ name: "Ava", score: 12 }, { name: "Ben", score: 7 }].

players[0].name reads the first player's name. In for (const p of players), p.score is each player's score in turn.

Add a record with players.push({ … }). Totals, counts and "the best so far" work just as before – you compare p.score, but keep the whole object p.

Worked example – see it

const players = [
  { name: "Ben", score: 22 },
  { name: "Nia", score: 6 },
  { name: "Sam", score: 19 }
]
console.log(players.length, players[2].score)

It prints:

3 19

The lesson, step by step