What does "as const" mean in TypeScript, and when should it be used?

In TypeScript, as const can also be used to narrow down types when passing arguments to functions. For example:

const point = [10, 20] as const;
function plot(x: 10, y: 20) { console.log(`Plotting at (${x}, ${y})`); }
plot(...point);  // Works because point is treated as [10, 20]

Here, as const TypeScript ensures that point is treated as a literal tuple, so TypeScript can infer the types of x and y more accurately and prevent type mismatches.