collect.js

sum()

The sum method returns the sum of all items in the collection:

collect([1, 2, 3]).sum();

//=> 6

If the collection contains nested arrays or objects, you should pass a key to use for determining which values to sum:

const collection = collect([
  { name: "JavaScript: The Good Parts", pages: 176 },
  { name: "JavaScript: The Definitive Guide", pages: 1096 }
]);

collection.sum("pages");

//=> 1272

In addition, you may pass your own callback to determine which values of the collection to sum:

const collection = collect([
  { name: "Desk", colors: ["Black", "Mahogany"] },
  { name: "Chair", colors: ["Black"] },
  { name: "Bookcase", colors: ["Red", "Beige", "Brown"] }
]);

const total = collection.sum(function(product) {
  return product.colors.length;
});

//=> 6

View source on GitHub

← take() →