Interface ReadonlyMap<K, V>

A Map object which cannot be written to. The Map object holds key-value pairs but doesn't remember the original insertion order of the keys (like JS would). Any value (both objects and primitive values) may be used as either a key or a value. Maps are the best choice for dynamic indexing/newindexing, whereas Objects are better for explicit indexing.

Example

// ReadonlyMaps are particularly useful for defining readonly-associations with non-numeric, non-string keys.
new ReadonlyMap<Enum.HumanoidRigType, () => void>([
    [Enum.HumanoidRigType.R6, () => {}],
    [Enum.HumanoidRigType.R15, () => {}],
]);
// Do not use Maps when you can easily index from an object:

// TS doesn't assume "x" | "y" are the only possible fields.
// You could manually type this as ReadonlyMap<"x" | "y", number>
const point = new ReadonlyMap([["x", 5], ["y", 10]]);
// this is typed as possibly undefined, which isn't ideal
print(point.get("x"));

// Instead use an object
const point = { x: 5, y: 10 } as const;
print(point.x);
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