Arrays
Learn how to achieve immutability principles with objects.
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Arrays are a bit trickier because they have multiple methods for adding and removing values. In general, you have to remember which methods create a new copy of the array and which change the original one.
Methods
The following table outlines the basic array methods:
| Safe methods | Mutating methods |
|---|---|
concat() |
push() |
slice() |
splice() |
map() |
pop() |
reduce() |
shift() |
reduceRight() |
unshift() |
filter() |
fill() |
reverse() |
|
sort() |
|
copyWithin() |
The basic array operations in most reducers are appending, deleting, and modifying an array.
To keep to the immutability principles, we can achieve these using the following methods:
The following code shows how to append to an array:
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