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JavaScript JavaScript Array Iteration Methods Combining Array Methods Working with Objects in Arrays

karan Badhwar
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karan Badhwar
Web Development Techdegree Graduate 18,135 Points
Posted by karan Badhwar
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karan Badhwar
Web Development Techdegree Graduate 18,135 Points

Help me understand this example. please

I saw an example for reduce (), but this is very confusing can somebody please explain me and is this a write way to write a syntax

const people = [
  {name: 'kyle', age: 26},
  {name: 'karan', age : 27},
  {name: 'Rahil', age : 27},
  {name: 'Vinay', age: 25}
];
const result = people.reduce(groupedPeople, person) => {
  const age = person.age;
  if (groupedPeople[age] == null) groupedPeople[age] = []
  groupedPeople[age].push(person)
}, {});

console.log(result);

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

This syntax is fine, but it is perhaps a bit complex for a first example.

Take a look at the thorough explanation on the MDN page for reduce(). It also contains several more examples of different levels of complexity.

karan Badhwar
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
karan Badhwar
Web Development Techdegree Graduate 18,135 Points
karan Badhwar
.a{fill-rule:evenodd;}techdegree seal-36
karan Badhwar
Web Development Techdegree Graduate 18,135 Points

Steven Parker, but if ever I encounter such type of syntax how do I know for future reference what's happening, coz now it takes me time to understand that

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

Reduce is perhaps one of the less intuitive things in JavaScript. Luckily, there are always handy online references. If I haven't it used much recently, I have to go look up the syntax myself.