List of Destructive and Non-Destructive JavaScript Array Methods

I can never remember which JavaScript Array methods are destructive and which are non-destructive.

A destructive method modifies the original array that the method is being run on. An example of this is pop:

const instruments = ["Guitar", "Drums", "Keyboard"];
instruments.pop();
// instruments = ["Guitar", "Drums"]

A non-destructive method does not modify the original array and instead returns a shallow copy of the original value. An example of this is map:

const instruments = ["Guitar", "Drums", "Keyboard"];
instruments.map(instrument => `${instrument} toot`);
// instruments = ["Guitar", "Drums", "Keyboard"]

Destructive Methods

• copyWithin
• fill
• pop
• push
• reverse
• shift
• sort
• splice
• unshift

Non-Destructive Methods

• concat
• entries
• every
• filter
• find
• findIndex
• findLast
• findLastIndex
• flat
• flatMap
• forEach
• Array.from()
• includes
• indexOf
• join
• keys
• lastIndexOf
• map
• reduce
• reduceRight
• slice
• some
• toLocaleString
• values