test("myArray is an array and has the correct initial value", () => {
  expect(Array.isArray(myArray)).toBe(true);
  // Initial value should be: ["Heine", 25, "Bob", 16] before any changes
  // After all operations, first element must still be 'Heine'
  expect(myArray[0]).toBe("Heine");
});

test("myArray does not contain 16 after pop", () => {
  // 16 should be removed
  expect(myArray.includes(16)).toBe(false);
});

test("myArray contains 21 at the end after push", () => {
  // 21 should be last element
  expect(myArray[myArray.length-1]).toBe(21);
});

test("myArray has 27 as the second element after replacement", () => {
  expect(myArray[1]).toBe(27);
});

test("myArray has correct final value", () => {
  expect(myArray).toEqual(["Heine", 27, "Bob", 21]);
});

test("prints the updated array as 'Heine,27,Bob,21'", () => {
  expect(captured).toContain("Heine,27,Bob,21");
});

user_code.test.js

Learn the fundamentals of JavaScript, the backbone of dynamic web development. Discover essential concepts like syntax, variables, data types, and operators. Explore how to use conditional statements, loops, and functions to create interactive and efficient programs. Master the building blocks of JavaScript and lay the groundwork for more advanced programming skills.

Discover the fundamentals of JavaScript, including its purpose and syntax. Learn how to work with the console for output and use comments to organize and document your code. These foundational skills will prepare you for a deeper exploration of JavaScript's capabilities.

Explore the building blocks of JavaScript by distinguishing between literals and variables. Understand the core data types, including `null` and arrays, and learn how to manipulate them using array methods.

Learn how to manipulate JavaScript's data types through essential operations. Master assignment, mathematical operations, incrementing and decrementing, comparisons, logical operations, and string concatenation.

Discover how to control the flow of your programs with conditional statements. Master `if`, `else`, and `else if` to instruct JavaScript on making decisions and executing code based on different conditions.

Streamline your code by mastering JavaScript's looping structures. Explore `while`, `do while`, and `for` loops, and learn how to control their behavior using `break` and `continue`. Unlock the power of loops to perform repetitive tasks efficiently.

Discover the power of functions in JavaScript. Learn how to define functions, work with arguments, and use the `return` statement to create reusable and efficient code. Mastering functions will enhance your ability to write clean and modular programs.

Challenge: Perform Array Operations

解答