1. To mutate the original array
add to original array
.push() - add to the end
.unshift() - add to the beginning
remove from original array
.pop() - remove from the end
.shift() - remove from the beginning
.splice() - remove from anywhere
others
.reverse() - reverse the array
.sort() - sort the array
.fill() - fill the array with a certain value
2. To create a new array
with the original array
.map() - transform the array
.filter() - filter the array
.slice() - slice the array
.concat() - merge two arrays
.flat() - flatten the array
.flatMap() - map and then flatten
3. With an array index
based on value
.indexOf() - find index of an element
based on test condition
.findIndex() - find index of an element
4. With an array element
based on test condition
.find() - find an element
5. To know if array includes something
based on value
.includes() - includes an element
based on test condition
.some() - if at least one element satisfies the condition
.every() - if all elements satisfy the condition
6. With a new string
based on the separator string
.join() - join the array into a string
7. To transform the value
based on the accumulator
.reduce() - reduce the array to a single value
8. To loop over the array
based on callback
.forEach() - loop over the array (does not create a new array)