Write a function that: 1. Takes 2 parameters - an array of #'s and a target # 2. Return all index pairs that equal the target #

indexPairs.js

/* 
Write a function that:
1. Takes 2 parameters - an array of #'s and a target #
2. Return all index pairs that equal the target #
3. Based on the values below the output should be 
[[3, 5]],[1, 6]] (e.g. 2 & 7 and 5 & 4)
*/ 
const nums = [1, 5, 12, 2, 3, 7, 4, 11, 15];
const target = 9

const getIndexPairsV2 = (list, target) => {
  const numbersMap = {}
  
  return list.map((number, index) => {
    numbersMap[number] = index
    const diff = numbersMap[target - number]
    if (diff !== undefined) return [index, diff]
    return false
  }).filter(e => e !== false)
}
                  
const result2 = getIndexPairsV2(nums, target)
console.log(result2)

const getIndexPairsV1 = (list, target) => {
  
  const pairs = []
  const len = list.length
  
  for(let count = 0; count <= len; count ++){
    let num1 = list[count]
    
    for(let count2 = count + 1; count2 <= len; count2 ++){
      let num2 = list[count2]
      
      if (num1 + num2 === target) {
        pairs.push([count, count2])
      }
    }  
  }
  
  return pairs
}

const result = getIndexPairsV1(nums, target)
console.log(result)