I would consider this an optimal 2017 solution: const count = (list) => list.filter((x) => x == 2).length . Then use it by calling count(list) where list is an ... ... <看更多>

In this JavaScript walkthrough, we take a look at " Array's Length Property Explained, JavaScript on Codecademy, Count Elements in an Array ... ... <看更多>

Scenario: // You have a javascript array that likely has some duplicate values and you would like a count of those values. const compressArray = arr => {. ... <看更多>

The length of an array is the number of elements it contains whereby it does not matter if those elements are valid objects or values or ... ... <看更多>

By definition, the length property of an array is an unsigned, 32-bit integer that is always numerically greater than the highest index in the array. The value ... ... <看更多>

So the length of an array can be found by simply taking a look at the current value of the length property of an array, but the count must be ... ... <看更多>