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Quick TrainerJavaScript Array Methods
Learn what each common JavaScript array method does and recall them in both directions.
Code32 items3 levelsDifficulty 2/5
Free · no signup · works on any device
Levels
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1
Basics
10 items
2
Iteration
10 items
3
Advanced
12 items
All 32 cards
push()
add to end
pop()
remove last
shift()
remove first
unshift()
add to start
indexOf()
find index of value
includes()
check if value exists
join()
array to string
slice()
copy a portion
concat()
merge arrays
reverse()
reverse order
map()
transform each element
filter()
keep matching elements
forEach()
run function for each
find()
first matching element
findIndex()
index of first match
some()
true if any match
every()
true if all match
reduce()
accumulate to one value
sort()
order elements
splice()
add/remove in place
flat()
flatten nested arrays
flatMap()
map then flatten
fill()
fill with a value
reduceRight()
reduce from the right
findLast()
last matching element
findLastIndex()
index of last match
at()
element at index
keys()
iterator of indexes
values()
iterator of values
entries()
iterator of key/value pairs
lastIndexOf()
last index of value
copyWithin()
copy part within array
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