I have this array:
array = ['bla', ['ble', 'bli'], 'blo', ['blu']]
I want it to be
array = ['bla', 'ble', 'bli', 'blo', 'blu']
Is there a simple function that can give me this particular result?
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4 Answers
Updated for 2020:
You can now use .flat() in all modern browsers.
var newArray = arr.flat([depth])
let result = ['bla', ['ble', 'bli'], 'blo', ['blu']].flat()
console.log(result);
result = ['bla', ['ble', ['bli', ['bom']]], 'blo', ['blu']].flat()
console.log(result);
result = ['bla', ['ble', ['bli', ['bom']]], 'blo', ['blu']].flat(2)
console.log(result);
result = ['bla', ['ble', ['bli', ['bom']]], 'blo', ['blu']].flat(Infinity)
console.log(result);You can use concat to do this:
array = [].concat.apply([], array)
If you need to do it recursively (nested nested arrays), I would probably do it like this:
function flatten(arr, result) {
if (typeof result === "undefined") {
result = [];
}
for (var i = 0; i < length; i++) {
if (Array.isArray(arr[i])) {
flatten(arr[i], result);
} else {
result.push(arr[i]);
}
}
return result;
}
1 Comment
p.s.w.g
+1 But this only works for arrays nested one level deep. e.g.
['bla', ['ble', ['bli']], 'blo', ['blu']] yields ['bla', 'ble', ['bli'], 'blo', 'blu']There is a new array prototype function called flat. Currently, Microsoft browsers and Samsung Internet do not support this function. The syntax is simple:
array.flat([depth])
depth is an optional variable that specifies how many layers to flatten. The default is 1. Read more about it here.
Comments
Edit: Please look at Dave's answer or p.s.w.g's answers instead - they're superior. This code is horrible and should not be used (I can't delete an accepted answer).
You could do something like this:
var arr = ['bla', ['ble', 'bli'], 'blo', ['blu']];
var newArr = arr.toString().split(',');
Explanation:
It's pretty simple. toString() on an array containing arrays creates a string with all the elements in the top level, so that [['abc']].toString() results in 'abc' regardless of how "deep" in the array it is. After that, you just split the string you get into an array using String.prototype.split and you've accomplished your goal
3 Comments
epascarello
Problem with splitting is if the content is a different type, you loose that type. AKA numbers would end up as strings.
dave
and if the string has a comma in it, it won't work
Some Guy
Those are both very good points. @dave Your answer does seem superior.
The other answers that have been provided are good, but here's my implementation of a recursive method that will flatten arrays arbitrarily nested to any depth:
var flatten = function(arr) {
var out = [];
for(var i = 0; i < arr.length; i++) {
out.push.apply(out, Array.isArray(arr[i]) ? flatten(arr[i]) : [ arr[i] ]);
}
return out;
};
Note this relies on Array.isArray, which may not be available in older browsers. You can replace that with another array test if this is a problem (e.g. arr[i].constructor == Array)