js

https://developer.mozilla.org/ru/docs/Web/JavaScript/Reference/Global_Objects/Array/flatMap
[{"item":"123","COUNT(item)":"1"},{"item":"333","COUNT(item)":"2"},{"item":"999","COUNT(item)":"1"}].flatMap(a=> a['COUNT(item)']).reduce((a,b)=>Number(a)+Number(b))
https://learn.javascript.ru/let-const

js strange behavior

foo();
a();

function foo() {
console.log(3);
}

var a = function() {
  console.log(2);
};

--------------------------------

http://latentflip.com/loupe/?code=JC5vbignYnV0dG9uJywgJ2NsaWNrJywgZnVuY3Rpb24gb25DbGljaygpIHsKICAgIHNldFRpbWVvdXQoZnVuY3Rpb24gdGltZXIoKSB7CiAgICAgICAgY29uc29sZS5sb2coJ1lvdSBjbGlja2VkIHRoZSBidXR0b24hJyk7ICAgIAogICAgfSwgMjAwMCk7Cn0pOwoKY29uc29sZS5sb2coIkhpISIpOwoKc2V0VGltZW91dChmdW5jdGlvbiB0aW1lb3V0KCkgewogICAgY29uc29sZS5sb2coIkNsaWNrIHRoZSBidXR0b24hIik7Cn0sIDUwMDApOwoKY29uc29sZS5sb2coIldlbGNvbWUgdG8gbG91cGUuIik7!!!PGJ1dHRvbj5DbGljayBtZSE8L2J1dHRvbj4%3D - визуализация евент луп
https://developer.mozilla.org/ru/docs/Games/Tutorials/2D_Breakout_game_pure_JavaScript - Арканоид