Iteration

First two of ascending index iteration

Handle base cases (0 and 1) separately when iterating through large number of times for a pattern:

if(array.length === 0) return "array is empty"
if(array.length === 1) {
  // when array length is one
  let onlyElement = array[0];
  
  return onlyElement;
}

if(array.length % 2 === 0) {
  // when array length is even
}

if(array.length % 2 === 1) {
  // when array length is odd
}

Control Flow

Always exit from an if condition

When you have multiple if conditions, make sure to return to prevent further evaluation.

Make Use of Boolean

const condition1: boolean = (i) => i % 3 === 0;
const condition2: boolean = (j) => j.toString().includes('someStrValue');

const someBooleanCheck: boolean = (x) => {
  return condition1 || condition2
}

for(let i=0; i<n; i++) {
  if(someBooleanCheck(i)) {
    // this behavior
  } else {
    // different behavior
  }
}

Lookahead

Be aware that when performing a lookahead, i+1 beyond the last element of array will be undefined.

Termination length:

if( someTerminalCondition || i+1 == array.length) { return "Current element (i) is the last element of the array. Next i does not exist and is beyond the array definition."}