When you need to…
Use…
In-place or copy
Reverse an array
reverse
In-place
Sort an array
sort
(pass in function for custom sort) In-place
Table 8-3. Array searching
When you want to know/find…
Use…
The index of an item
indexOf
(simple values),
findIndex
(complex values)
The last index of an item
lastIndexOf
(simple values)
The item itself
find
Whether the array has an item that matches some criteria
some
Whether all elements in the array matches some criteria
every
Table 8-4. Array transformation
When you want to…
Use…
In-place or copy
Transform every element in an array
map
Copy
Eliminate elements from an array based on some criteria
filter
Copy
Transform an entire array into another data type
reduce
Copy
Convert elements to strings and join together
join
Copy
Conclusion | 145
