Space complexity

• Measures the memory aspect of an algorithm
• Measures how much additional memory is used as part of execution
• What consumes space/memory?
• Variables
• Data structures
• Function Calls
• Allocations

$O(1)$

// No assignments are made beyond for counter
function foo(coll) {
  for (let i = 0; i < coll.length; i++) {
    console.log("Hey!");
  }
}

$O(n)$

// Memory allocation increases as the input increases
function foo(coll) {
  let hiArr = [];
  for (let i = 0; i < coll.length; i++) {
    hiArr.push('hi');
  }
}