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Lodash _.reduce


The lodash _.reduce method is a powerful tool for reducing an array to a single value based on an iteratee function's logic. This function has two primary parameters: the array to iterate through and a callback function that determines how each item will be reduced. The callback function is executed with four arguments: the accumulated value, the current item in the iteration, the current index, and the original array.

Here is the general syntax for using lodash _.reduce:

_.reduce(collection, iteratee, [accumulator])

collection is the array or object to be iterated over, and iteratee is the function that is executed on each item in the collection. The optional accumulator parameter provides an initial value for the accumulation process.

The iteratee function can take two or more parameters. The first parameter, accumulator, is the value that is constantly passed to the function after each iteration. The second parameter, currentValue, is the value of the current array element being assessed. The two other optional parameters that can be included are the index of the current element and the collection itself.

Here is an example of using lodash _.reduce to sum the values of an array of numbers:

const myArray = [1, 2, 3, 4];

_.reduce(myArray, (accumulator, currentValue) => {
  return accumulator + currentValue;
// Returns 10

In this example, the _.reduce method iterates through each element of the myArray and adds its value to the accumulator value. Once the iteration is complete, the method returns the final value of accumulator.

The lodash _.reduce method is a useful tool for any situation that requires reducing an array to a single value. Its versatility and customizable iteratee function make it a valuable asset in any developer's toolkit.