JS array methods you should know (Part2)
Hey there, let’s continue to know some other useful
methods.😁
1-Flat():
This method return an one-dimensional array where all
sub–arrays element are concatenated into a one.
Let me show you.
const nums = [11,[2,31],-4,[51,6]];
const nums2 = nums.flat();
console.log(nums2);
and the result is:
(6) [11, 2, 31, -4, 51, 6]
2-sort():
we all know what it does 😋! This method sorted a specific
array. And the result is within the existing array No need for example here.
3-isArray():
I know it’s kind of weird. but this method return a Boolean
value to indicate whether an object is an array or no. you may ask why we use
is it?? 😕Well since js use dynamic types you can’t always be confident of variable
type. For example in API calls when you store the result in a variable. You don’t
want to apply array method before being sure ! Trust me you will get a very
annoying bug 😂.
4-Find():
A very useful method to get an element with a specific
conditions, the return type is the element type.of course it execute a function to compare.
const inventory = [
{name: 'apples', quantity: 2},
{name: 'cherries', quantity: 8},
{name: 'bananas', quantity: 0},
{name: 'cherries', quantity: 5},
{name: 'cherries', quantity: 15}
];
const result = inventory.find( ({ name }) => name === 'cherries' );
console.log(result);
And the result is an object : {name: 'cherries',
quantity: 8}
5-findIndex():
Nearly does the same as the previous one, but the
return isn’t an element by its index .so the syntax is the same except the
return type!
6-Join():
As you have seen split() , now let’s see join .
It returns the array’s element as a string. By specifying
the separator inside it we can customize our result.
const elements = ['Sun', 'Earth', 'Moon'];
console.log(elements.join());
// output: "Sun,Earth,Moon"
console.log(elements.join(''));
// output: "SunEarthMoon"
console.log(elements.join('-'));
// output: "Sun-Earth-Moon"
7-Reverse():
As the name indicates, this method return a reversed
array from the existing one.
const nums = [11,2,31,-4,51,6];
const result = nums.reverse();
console.log(result);
And the result for sure : [6, 51, -4, 31, 2, 11]
A very useful case for this method is to reverse a
string . know of it a little and try to use ‘split’ and ‘join’ method that we
have seen. Don’t jump to the solution fast .😉
Solution:
const str = '!TIoD ym ot emoclew';
const res =str.split('').reverse().join('');
console.log(res)
this is all folks. Hope you like it. wait you want
more😮 ? ok see you in part3.😍
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