CoffeeScript filters the array

Filter the array

Problem

You want to filter arrays based on Boolean criteria.

Solution

Using Array.filter (ECMAScript 5)： array = [1..10]

array.filter (x) -> x > 5
# => [6,7,8,9,10]

In the previous implementation of EC5, Array's prototype could be extended by adding a filter function that accepts a callback and filters itself, collecting elements of the callback function that return true.

# 扩展 Array 的原型
Array::filter = (callback) ->
  element for element in this when callback(element)

array = [1..10]

# 筛选偶数
filtered_array = array.filter (x) -> x % 2 == 0
# => [2,4,6,8,10]

# 过滤掉小于或等于5的元素
gt_five = (x) -> x > 5
filtered_array = array.filter gt_five
# => [6,7,8,9,10]

Discuss

This method is similar to Ruby's Array's .select method.