JSFiddle - React, Tailwind, and code Playground

by sandro_paganotti

JavaScript

Array.prototype.flatten = function(){
    for(var x=0; x<this.length; x++){
        if(Array.isArray(this[x])){
            this.splice.apply( this,[x,1].concat(this[x]));
            if(Array.isArray(this[x])) x--;
        }
    }
    return this;
}
                               
console.log([1,2,3,[[1],2,3]].flatten())