JavaScript: How to remove all the square brackets inside the outer array? [duplicate]

Question

var arrayX = [ ["fire", "lightning"], [3, "ice"], [85], ["wind", "earth", 0] ];

In the example above, arrayX consists of four elements, each of which is also an array. As it stands now, arrayX.length equals 4.

I wonder if it is possible to remove all the four pairs of square brackets inside, leaving only the most outer bracket, so that the computer can now count the total number of all the individual elements in arrayX. I mean, like this:

var arrayX = ["fire", "lightning", 3, "ice", 85, "wind", "earth", 0];

Now, arrayX.length returns 8, and this is the number I want to get. I started to learn programming just several days ago, so I'm not sure how to go about this. Thank you in advance.

Create an array and add all the elements to it, by traversing the original array using for loop, or use arrayX.join().split(',') but here all the values are converted to string, but length will be 8, as per the question. — rajuGT
– rajuGT, Commented Dec 11, 2015 at 15:13

epascarello · Accepted Answer · 2015-12-11 15:13:59Z

8

There is no need to loop

arrayX = [].concat.apply([], arrayX);

answered Dec 11, 2015 at 15:13

epascarello

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2 Comments

Nina Scholz Over a year ago

it works only if the array is not nested.

epascarello Over a year ago

@NinaScholz Works fine for OPs case. I love when people add new requirements that do not matter in the OPs case.

bcr · Accepted Answer · 2015-12-11 15:12:57Z

1

Use Array.prototype.reduce():

var flattened = [ ["fire", "lightning"], [3, "ice"], [85], ["wind", "earth", 0] ].reduce(function(a, b) {
  return a.concat(b);
}, []);

docs here

answered Dec 11, 2015 at 15:12

bcr

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Comments

Andrew Bone · Accepted Answer · 2019-08-05 08:49:19Z

0

I'm a fan of the concat method myself

function concatArray() {
  var arrayX = [
    ["fire", "lightning"],
    [3, "ice"],
    [85],
    ["wind", "earth", 0]
  ];
  arrayX = [].concat.apply([], arrayX);
  console.log(arrayX.length);
}

concatArray();

edited Aug 5, 2019 at 8:49

answered Dec 11, 2015 at 15:18

Andrew Bone

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2 Comments

Andrew Bone Over a year ago

Was my answer wrong?

arnoldssss Over a year ago

you seem happy , no one here likes that in my exp, avoid 'fan' , 'excelent', 'super' keywords

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