JS Built-ins
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ArrayArray.ofbeginner

Array.of() — avoid the single-number trap

📖 Usage Example
// Ambiguous new Array:
new Array(3)         // → [empty x 3]  (sparse)
new Array(1, 2, 3)   // → [1, 2, 3]
// Always predictable Array.of:
Array.of(3)          // → [3]

Prefer Array.of() over new Array() for clarity — its behavior is consistent regardless of argument count.

Array.of() vs new Array()

new Array(7) creates a sparse array with 7 empty slots, not an array containing 7. Array.of(7) always creates an array whose single element is 7. This distinction makes Array.of safer when you only have one value.

Challenge: Implement safeArrayOf that always wraps n in an array (i.e. returns [n]), never a sparse array of length n.

safeArrayOf(7)   // → [7]   not [ <7 empty slots> ]
safeArrayOf(0)   // → [0]
💡 Hints (2)
  • • `Array.of(n)` always creates `[n]` regardless of what `n` is.
  • • `new Array(n)` treats a single numeric argument as the desired length, not a value.