Code Talk - Reduce

gistfile1.js

const colorArr = ['red', 'blue', 'green', 'orange'];

const reduceArr = colorArr.reduce((accumulator, currentItem, currentIndex, entireArrayIteratingOn) => {
  accumulator.push(currentItem)

  return accumulator
}, [])
console.log(reduceArr)

const reduceObj = colorArr.reduce((accumulator, currentItem, currentIndex, entireArrayIteratingOn) => {
  accumulator[currentItem] = `item-${currentIndex}`

  return accumulator
}, {})
console.log(reduceObj)




const colorArr = ['red', 'blue', 'green', 'orange'];

const mapWithIf = colorArr.map((currentColor) => {
  if (currentColor === colorArr[1]) {
    return currentColor;
  }
});
console.log(mapWithIf);

const mapWithIfFilter = colorArr.map((currentColor) => {
  if (currentColor === colorArr[1]) {
    return currentColor;
  }
})
.filter(t => t);
console.log(mapWithIfFilter);

const filterOne = colorArr.filter(currentColor => currentColor === colorArr[1])
console.log(filterOne);

const forEachIf = []
colorArr.forEach((currentColor) => {
  if (currentColor === colorArr[1]) {
    forEachIf.push(currentColor);
  }
});
console.log(forEachIf);

const reduceIf = colorArr.reduce((accumulator, currentColor) => {
  if (currentColor === colorArr[1]) {
    accumulator.push(currentColor)
  }

  return accumulator
}, [])
console.log(reduceIf)




const personObjOne = {
  name:'jane',
  hair: 'blonde',
  eyes: 'blue',
  height: 5.7,
  awesome: true,
};

const personObjTwo = {
  name:'john',
  hair: 'brown',
  eyes: 'green',
  height: 6,
  awesome: true,
};
 
const reduceArrayIf = [personObjOne, personObjTwo].reduce((accumulator, currentPerson) => {
  const { hair } = currentPerson
  
  if (hair === 'blonde') {
    accumulator.push(currentPerson)
  }

  return accumulator
}, []);
console.log(reduceArrayIf);

const reduceNewObject =  [personObjOne, personObjTwo].reduce((accumulator, currentPerson) => {
  const { awesome, name } = currentPerson
  
  if (awesome) {
    accumulator.push(name)
  }

  return accumulator
}, []);
console.log(reduceNewObject)

const mapNewObj1 =  [personObjOne, personObjTwo].map((currentPerson) => {
  const { awesome, name } = currentPerson
  
  if (awesome) {
   return name
  }
});
console.log(mapNewObj1)

const mapNewObj2 =  [personObjOne, personObjTwo].map((currentPerson) => {
  const { name } = currentPerson
  
  if (name === 'jane') {
    return name
  }
});
console.log(mapNewObj2)

const mapNewObj3 =  [personObjOne, personObjTwo].reduce((accumulator, currentPerson) => {
  const { name } = currentPerson
  
  if (name === 'jane') {
    accumulator.push(name)
  }

  return accumulator
},[]);
console.log(mapNewObj3)



const partialPerson1 = {
  name: 'jimi',
  height: 5,
}
const partialPerson2 = {
  eyes: 'blue',
  hair: 'brown',
}
const partialPerson3 = {
  eyes: 'green',
  hair: 'blonde',
}

const newPerson = {...partialPerson1, ...partialPerson2}
console.log(newPerson)

const personIf = [partialPerson2, partialPerson3].reduce((accumulator, partialPerson) => {
  const { eyes } = partialPerson
  
  if (eyes === 'green') {
    accumulator = { ...partialPerson }
  }

  return accumulator
}, {});
console.log(personIf)

const personOptions = [partialPerson2, partialPerson3]
const personBuild = personOptions.reduce((accumulator, partialPerson, index, allPassedInItems) => {
  const { eyes } = partialPerson
  // index
  // personOptions -> allPassedInItems
  // allPassedInItems
  if (eyes === 'green') {
    accumulator = { ...accumulator, ...partialPerson }
  }

  return accumulator
}, partialPerson1);
console.log(personBuild)