Map vs for each

chars = ['Hello' , 'world!!!'] ;
var retVal = chars.forEach(function(word){
  console.log("Saving to db: " + word) 
})
console.log(retVal) //undefined

chars = ['Hello' , 'world!!!'] ;
var lengths = chars.map(function(word){
  return word.length
}) 
console.log(lengths) //[5,8]

Source: stackoverflow.com

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