The following code
function steamrollArray(arr) {
// I'm a steamroller, baby
return arr.flat();
}
steamrollArray([1, [2], [3, [[4]]]]);
returns
arr.flat
is not a function
I tried it in Firefox and Chrome v67 and the same result has happened.
What's wrong?
The flat
method is not yet implemented in common browsers (only Chrome v69, Firefox Nightly and Opera 56). It’s an experimental feature. Therefore you cannot use it yet.
You may want to have your own flat
function instead:
Object.defineProperty(Array.prototype, 'flat', {
value: function(depth = 1) {
return this.reduce(function (flat, toFlatten) {
return flat.concat((Array.isArray(toFlatten) && (depth>1)) ? toFlatten.flat(depth-1) : toFlatten);
}, []);
}
});
console.log(
[1, [2], [3, [[4]]]].flat(2)
);
The code was taken from here by Noah Freitas originally implemented to flatten the array with no depth
specified.