uhop

'use strict';

class ListHead {
  constructor(head = null, next = 'next', prev = 'prev') {
    if (head instanceof ListHead) {
      ({nextName: this.nextName, prevName: this.prevName, head: this.head} = head);
      return;
    }
    this.nextName = next;
    this.prevName = prev;

uhop

let flag;

const detectWebp = () => {
  if (typeof flag == 'boolean') return flag;
  const canvas = document.createElement('canvas');
  flag = !!(canvas.getContext && canvas.getContext('2d') && /^data:image\/webp;/.test(canvas.toDataURL('image/webp')));
  return flag;
};

export default detectWebp;

uhop

What

We need to setup an S3 bucket so we can use AWS JS SDK to upload files from a web application only for logged in users.

We already have a Cognito user pool, e.g., self-managed, and/or tied to a corporate SSO or social networks. Users may have different permissions depending on custom groups they are on. There is an app client, which is used to authenticate users in our web app.

How

uhop

'use strict';

const roll = pattern => {
  const samples = [];
  let counter = 0;
  for(;;){
    if (samples.length >= pattern.length) {
      samples.shift();
    }
    const sample = Math.floor(Math.random() * 6) + 1;

uhop

'use strict';

const AWS = require('aws-sdk');

let profile = process.env.LAMBDA_TASK_ROOT && process.env.AWS_EXECUTION_ENV ? '' : 'default';

const profileIndex = process.argv.indexOf('--profile');
if (profileIndex > 0 && profileIndex + 1 < process.argv.length) {
  profile = process.argv[profileIndex + 1];
}

uhop

'use strict';

const iterate = async function*(client) {
  const params = {MaxItems: '100'};
  for (;;) {
    const data = await client.listDistributions(params).promise(),
      list = data.DistributionList,
      items = list.Items;
    if (items) {
      yield items;

uhop

'use strict';

const List = require('./List');

class Cache {
  constructor(capacity = 10) {
    this.capacity = capacity;
    this.size = 0;
    this.list = new List();
    this.dict = {};

uhop

'use strict';

const zig = tree => {
  const newTree = tree.l,
    parent = (newTree.p = tree.p);
  if (parent) {
    if (parent.l === tree) parent.l = newTree;
    else parent.r = newTree;
  }
  tree.p = newTree;

uhop

'use strict';

class ListNode {
  constructor() {
    this.prev = this.next = this;
  }
}

const pop = head => {
  const rest = head.next;

uhop

'use strict';

// using heap implementation from https://github.com/heya/ctr under the BSD-3 license

class Heap {
  constructor(less = (a, b) => a < b, arrayLike = []) {
    this.less = less;
    this.array = Heap.make(Array.from(arrayLike), this.less);
  }