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Cover image for I'll teach you 7 Array methods. (with animations!)
Fredy Sandoval
Fredy Sandoval

Posted on • Edited on • Originally published at fredy.dev

I'll teach you 7 Array methods. (with animations!)

map

Creates a new array populated with the results of a provided function on every element.

[1, 2, 3].map( n => n * 2 ); // [2, 4, 6]
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11

filter

Creates a Copy of a portion of a given array, filtered down to just the elements from the given array that pass the test, keep in mind that changes of your first array will affect your copy.

[1,2,3].filter( n => n !== 2 ); // [1,3]
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22

find

Stops and returns the first element in the provided array that satisfies the provided testing function, otherwise returns undefined.

[1,2,3].find( n => n == 2 ) // 2
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33

findIndex

Returns the index of the first element that satisfies the provided testing function. Otherwise -1 is returned.

[1,2,3].findIndex( n => n == 2) // 1
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44

fill

Changes all elements in an array to a static value, from a start index (default 0) to an end index (default array.length). It returns the modified array.

[1,2,3].fill('Txt', 1,2) // [1,'Txt', 3]
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77

every

Tests all elements in the array. After finished returns a Boolean value

[2,2,2].every( n => n == 2 ) // true
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88

some

Tests whether at least one element in the array passes the test implemented by the provided function.

[1,2,3].some( n => n == 2) // true
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Latest comments (18)

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rabeehco profile image
Rabeeh Ebrahim

Thanks for creating this. Nice content.

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chiki1601 profile image
Miss Pooja Anilkumar Patel

Cool

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said_mounaim profile image
Said Mounaim

Usefull! Thanks for sharing

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simmbiote profile image
JBS

Pretty neat. The gif for .fill is not quite right.

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jmfayard profile image
Jean-Michel 🕵🏻‍♂️ Fayard

How did you produce those animations ?
Such a great teaching tool

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themfon profile image
Mfon

Very engaging. I love the gifs

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ruleenugroho profile image
ruleenugroho

very usefull, Thanks

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codewithtee profile image
Tabassum Khanum

Very Helpful!

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hasobi profile image
Hasobi

excellent content! love it!

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tracygjg profile image
Tracy Gilmore

Fredy,
Nice article - love the animation but I think it could do with two examples for the every and some methods to demonstrate complete and early exit.