JSFiddle - React, Tailwind, and code Playground

JavaScript

Array.prototype.partition = function(length) {
  var result = [];
  for(var i = 0; i < this.length; i++) {
    if(i % length === 0) result.push([]);
    result[result.length - 1].push(this[i]);
  }
  return result;
};
alert(JSON.stringify([1,2,3,4,5,6,7,8,9].partition(3)));