array.js

export const shuffle = (array) => {
  for (let i = array.length - 1; i > 0; i--) {
    let rand = Math.floor(Math.random() * (i + 1));
    [array[i], array[rand]] = [array[rand], array[i]]
  }
}

export const filter = (arr, cb) => {
  var r = []; 
  for (let i = 0, c = arr.length; i < c; i++) {
    let value = arr[i];
    if (cb.call(cb, value, i, arr)) r.push(value);
  }
  return r;
}

export const find = (arr, cb) => {
  for (let i = 0, c = arr.length; i < c; i++) {
    if (cb.call(cb, arr[i], i, arr)) return arr[i];
  }
};

export const inArray = (prop, array) => array.indexOf(prop) !== -1; 

export const first = (list) => list[0];

export const last = (list) => list[list.length - 1]; 

export const max = (data) => Math.max.apply(null, data);