For loop optimizations

forLoop.js

// Here I'll demonstrate an easy way to optimize a for loop

// Here, I'm setting the for loop's condition as i < stringToPrint.length
// Totally valid, but each time I loop back to the beginning, I check whether
// the condition is true, which means I'll have to re-evaluate the value
// of stringToPrint.length, which is unchanging. This is inefficient, because
// I'll have to do this as many times as the string is long.

const originalLoop = () => {
  const stringToPrint = 'Hello world';
  for (let i = 0; i < stringToPrint.length; i++) {
    console.log(stringToPrint[i]);
  };
};

// Instead, I can make stringToPrint.length a constant. This way, I only
// need to evaluate its value once.

const optimizedLoop = () => {
  const stringToPrint = 'Once more, with feeling!';
  const stringLength = stringToPrint.length;
  for (let k = 0; k < stringLength; k++) {
    console.log(stringToPrint[k]);
  }
}