Group by, and sum, and generate an object for each array in JavaScript

by 
let data =[
    {"id":"2018", "name":"test", "total":1200},
    {"id":"2019", "name":"wath", "total":1500},
    {"id":"2019", "name":"wath", "total":1800},
    {"id":"2020", "name":"zooi", "total":1000},
];

let map = data.reduce((prev, next) =>{
  if (next.id in prev) {
    prev[next.id].total += next.total;
  } else {
     prev[next.id] = next;
  }
  return prev;
}, {});

let result = Object.keys(map).map(id => map[id]);

console.log(result);

More Related Contents:

  1. Sum JavaScript object propertyA values with the same object propertyB in an array of objects
  2. Pick data from array of objects and return new object
  3. How to get all the values associated with an object in array?
  4. How to remove all duplicates from an array of objects?
  5. Group array of object nesting some of the keys with specific names
  6. Remove array element based on object property
  7. Sort array of objects by single key with date value
  8. How to add an object to an array
  9. Add property to an array of objects
  10. How to update an “array of objects” with Firestore?
  11. How can I get the index of an object by its property in JavaScript?
  12. Why Array.indexOf doesn’t find identical looking objects
  13. What is the performance of Objects/Arrays in JavaScript? (specifically for Google V8)
  14. Why do empty JavaScript arrays evaluate to true in conditional structures?
  15. Create an empty object in JavaScript with {} or new Object()?
  16. How do I remove an object from an array with JavaScript? [duplicate]
  17. break array of objects into separate arrays based on a property
  18. Uncaught TypeError: Object.values is not a function JavaScript
  19. JavaScript: Remove duplicates of objects sharing same property value
  20. Filtering array of objects by searching nested object properties
  21. traversing through JSON string to inner levels using recursive function
  22. Recursive depth function on an array
  23. Combining two arrays to form a javascript object
  24. Declaring array of objects
  25. Node.js – console.log does not show items in array but instead shows [Object]
  26. Create a dynamic nested object from array of properties
  27. Converting Array of Objects into Array of Arrays
  28. Difference between ( for… in ) and ( for… of ) statements?
  29. Find object having maximum value for the `id` property in an array of objects
  30. How can I remove an element from a list, with lodash?

Leave a Comment