JS Built-ins
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ArrayArray.prototype.fillintermediate

Array.prototype.fill() — create zero-filled array

📖 Usage Example
const zeros = new Array(5).fill(0)
zeros  // → [0, 0, 0, 0, 0]

Combine new Array(n) with fill(0) to create a zero-initialized array of length n.

Array.prototype.fill() — initializing arrays

A common pattern is to create a fixed-length array initialized to a default value. new Array(n).fill(0) creates an n-element array of zeros without using a loop.

Challenge: Implement createMatrix(n) that returns an array of n zeros.

createMatrix(5) // → [0, 0, 0, 0, 0]
createMatrix(0) // → []
💡 Hints (2)
  • • `new Array(n)` creates a sparse array with `n` slots — without `.fill()` each slot is `empty`.
  • • `.fill(0)` replaces every sparse slot with an actual `0` value.