TypeScript Tuple Type

let strictTuple: [string, number, boolean];

strictTuple = ["hello", 42, true]; // Valid

// Error: Type 'number' is not assignable to type 'string' at index 0.
strictTuple = [42, "hello", true]; 

// Error: Source has 2 element(s) but target requires 3.
strictTuple = ["hello", 42]; 

let data: [string, number] = ["TypeScript", 2023];

const text = data[0]; // Inferred as 'string'
const year = data[1]; // Inferred as 'number'

// Error: Tuple type '[string, number]' of length '2' has no element at index '2'.
const outOfBounds = data[2]; 

let optionalTuple: [string, number, boolean?];

optionalTuple = ["test", 1];       // Valid, length is 2
optionalTuple = ["test", 1, true]; // Valid, length is 3

type OptLength = typeof optionalTuple.length; // Type is 2 | 3

// Rest element at the end
let stringAndNumbers: [string, ...number[]];
stringAndNumbers = ["start", 1, 2, 3, 4];

// Rest element in the middle
let boundedTuple: [boolean, ...string[], number];
boundedTuple = [true, "a", "b", "c", 99];

let userRecord: [name: string, age: number, isActive: boolean];
userRecord = ["Alice", 30, true];

let immutableTuple: readonly [string, number] = ["fixed", 100];

// Error: Cannot assign to '0' because it is a read-only property.
immutableTuple[0] = "mutated"; 

// Error: Property 'push' does not exist on type 'readonly [string, number]'.
immutableTuple.push(200); 

let mutableTuple: [string, number] = ["a", 1];

mutableTuple.push(2); // Valid at compile-time
mutableTuple.push("b"); // Valid at compile-time

// Error: Argument of type 'boolean' is not assignable to parameter of type 'string | number'.
mutableTuple.push(true); 

// Error: Tuple type '[string, number]' of length '2' has no element at index '2'.
const hiddenElement = mutableTuple[2];