reduce method in react js code example

Example 1: reduce method in javascript array of bjects

var arr = [{x:1}, {x:2}, {x:4}];
arr.reduce(function (acc, obj) { return acc + obj.x; }, 0); // 7
console.log(arr);

Example 2: reduce javascript

let sum = arr.reduce((curr, index) => curr + index);

Example 3: syntax of reduce in js

[1,2,3,4,5].reduce((acc, current)=>acc+current, 0)

Example 4: reduce javascript

/* this is our initial value i.e. the starting point*/
const initialValue = 0;

/* numbers array */
const numbers = [5, 10, 15];

/* reducer method that takes in the accumulator and next item */
const reducer = (accumulator, item) => {
  return accumulator + item;
};

/* we give the reduce method our reducer function
  and our initial value */
const total = numbers.reduce(reducer, initialValue)

Example 5: reduce javascript

function flattenArray(data) {
  // our initial value this time is a blank array
  const initialValue = [];

  // call reduce on our data
  return data.reduce((total, value) => {
    // if the value is an array then recursively call reduce
    // if the value is not an array then just concat our value
    return total.concat(Array.isArray(value) ? flattenArray(value) : value);
  }, initialValue);
}