ljharb

Array Iteration

https://gist.github.com/ljharb/58faf1cfcb4e6808f74aae4ef7944cff

While attempting to explain JavaScript's reduce method on arrays, conceptually, I came up with the following - hopefully it's helpful; happy to tweak it if anyone has suggestions.

Intro

JavaScript Arrays have lots of built in methods on their prototype. Some of them mutate - ie, they change the underlying array in-place. Luckily, most of them do not - they instead return an entirely distinct array. Since arrays are conceptually a contiguous list of items, it helps code clarity and maintainability a lot to be able to operate on them in a "functional" way. (I'll also insist on referring to an array as a "list" - although in some languages, List is a native data type, in JS and this post, I'm referring to the concept. Everywhere I use the word "list" you can assume I'm talking about a JS Array) This means, to perform a single operation on the list as a whole ("atomically"), and to return a new list - thus making it mu

nybblr

// Create a Promise that resolves after ms time
var timer = function(ms) {
  return new Promise(resolve => {
    setTimeout(resolve, ms);
  });
};

// Repeatedly generate a number starting
// from 0 after a random amount of time
var source = async function*() {

yyx990803

• New Features
• Dist Files Adjustments
• [email protected]
• JSX Improvements
• vue-server-renderer
• vue-template-compiler
• Fixed

New Features

nepsilon

Understanding HTTP’s Transfer-Encoding: chunked

Simply put, Transfer-Encoding: chunked, in a HTTP response header, tells us the body will be received in several chunks.

This is ideal in 2 scenarios:

1. When the size of the body isn’t known in advance, like when generating output from a database.
2. When the size of the body is too big to be fully loaded in RAM before being sent to the client.

In practice, the body has each of its chunks separated with X\r\n, where X is the size of the chunk in hexadecimal. For instance:

MarcoWorms

function createStore (reducers) {
  var state = reducers()
  const store = {
    dispatch: (action) => {
      state = reducers(state, action) 
    },
    getState: () => {
      return state
    } 
  }

nepsilon

2 front-end tips to keep in mind

1. Stop using .innerHTML = ''; when removing children to a DOM element.

On modern browsers it seems to be about 400× (!!) slower than this DOM-friendly method:

while (el.firstChild)
    el.removeChild(el.firstChild);

MadLittleMods

Just some notes and references for myself.

• In bash, you can access your C:\ drive via /mnt/c/
• ~ = C:\Users\MLM\AppData\Local\lxss\home\mlm and is different from your Windows user directory C:\Users\MLM

How to google things

nepsilon

CLI: Output the difference between 2 files

Thinking of using diff? Try comm, its sole purpose is to compare 2 sorted files line by line.

Show lines in A.txt but NOT in B.txt:

comm -2 -3 A.txt B.txt

If the files aren’t sorted, use:

greim

How you can help reduce node_modules bloat

This recent reddit thread reveals discontent among the web development community about the sheer volume of stuff in a typical node_modules dir. 140MB in this case!

Is it a design flaw in npm?

Opinions in the thread varied from "I'm surprised npm even works" to "everything is fine". I'm not going to offer an opinion, just these two observations:

1. node_modules dirs typically do contain lots of stuff that doesn't need to be there.
2. The latest version mitigates overall size by flattening the dependency tree, but some of the bloat is beyond npm's control.

peterbe

import StringIO
import gzip
import os
import subprocess
import time


def compiler(path):
    cmd = 'java -jar compiler-latest/compiler.jar -O advanced'.split()
    cmd.append(path)