Typically, a tuple is an array with fixed size and known datatypes. This is to say you'd use a tuple for a static, well-defined array.
Let's have an example
We have a tuple of primary colors with known values
const primaryColors: [string, string, string] = ['#ff0000', '#00ff00', '#0000ff'];
If we exclude one of the
string in the definition of the types, we get an error. If we don't include all three primary colours, we also get an error. i.e
Doing this throws an error
const primaryColors: [string, string] = ['#ff0000', '#00ff00', '#0000ff']; // throws an error
Doing this also throws and error
const primaryColors: [string, string, string] = ['#00ff00', '#0000ff']; // throws an error
Using an array instead
If we were to store the same data in an array, we'd simply do this.
const primaryColors: string = ['#ff0000', '#00ff00', '#0000ff'];
Note: We can also store other datatypes in a tuple. Here's an example.
const nameAge: [string, number] = ['Osinachi', 10011];
Same as arrays
const nameAge: (string | number) = ['Osinachi', 10011];
Why do we need tuples?
To store data in an unchanging array.
So, tell me other uses of tuples you've come across. If you have never used TypeScript, check out their docs here. If you want an interesting introduction, check out this Scrimaba tutorial on TypeScript