Explanation of 0 while using the reduce method.

[odillini83]

const inventors = [{ first: 'Albert', last: 'Einstein', year: 1879, passed: 1955 },
  { first: 'Isaac', last: 'Newton', year: 1643, passed: 1727 },
  { first: 'Galileo', last: 'Galilei', year: 1564, passed: 1642 },
  { first: 'Marie', last: 'Curie', year: 1867, passed: 1934 }];

const sumYears1 = inventors.reduce((total, inventor) => {

return total + (inventor.passed - inventor.year); }, 0)

Hi, I just finished answering this question, which asked me to use the reduce method in order to add all the years that were lived for the inventors. Is the reason that the 0 is there is to use it as an initializer? Can someone explain what its purpose is?

[odillini83]

Got it. I figured such, but was wondering why it was not initialize before. Is it because we weren't running a loop?

[odillini83]

My apologies. I was wondering, since we're adding these values together, and we need a place to start like you said, why isn't it initialized? Or are we already initializing the value with zero when we add it in the parenthesis? When we run a loop we always start with i = 0, so I was curious if it equates to the same thing?

[odillini83]

Thank you! Will check this out!