Сергей Соколов

function countSymbols(s) {
  return s.split('').reduce(
    (p,c) => (p.hasOwnProperty(c)?p[c]++:p[c]=1, p), {}
  );
}
var r = countSymbols('hello'); // {"h":1,"e":1,"l":2,"o":1}

function bad( obj, name) {
  return eval('obj.' + name);     
}
bad(r, 'foo.bar'); // 'value'

function better( obj, name) {
  var parts = name.split('.'), i, cursor = r;
  
  for( i = 0; i < parts.length; i++) {
    if( !cursor.hasOwnProperty( parts[i])) throw('No such property: ' + parts[i]);
    cursor = cursor[parts[i]];
  }
  
  return cursor;
}

better(r, 'foo.bar'); // 'value'

<div class="textfield" contentEditable="true">напиши-ка!
</div>

.textfield {
	font-size:16px;
	color:white;
	min-height:16px;
	line-height:20px;
	width:200px;
	border:1px solid #999;
	background:  url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAIAAAAC64paAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAACtJREFUeNpiNDY2ZiAXMDFQAEY1j2oe1TyoNLNoOu0nX/P1fY4D42yAAAMA7aYDxR1GwC8AAAAASUVORK5CYII=')
}
body {background:#333; font-family:Arial, sans-serif}

<textarea rows="1" cols="20" id="ta1" class="textfield">напиши-ка!
</textarea>

var ta1 = document.getElementById('ta1');
ta1.addEventListener('input', function(){
	var rows = Math.ceil( ta1.scrollHeight / 20 ) - 1;
	ta1.style.height = 20 * rows + 'px';
});

closest: function( selectors, context ) {
		var cur,
			i = 0,
			l = this.length,
			matched = [],
			targets = typeof selectors !== "string" && jQuery( selectors );

		// Positional selectors never match, since there's no _selection_ context
		if ( !rneedsContext.test( selectors ) ) {
			for ( ; i < l; i++ ) {
				for ( cur = this[ i ]; cur && cur !== context; cur = cur.parentNode ) {

					// Always skip document fragments
					if ( cur.nodeType < 11 && ( targets ?
						targets.index( cur ) > -1 :

						// Don't pass non-elements to Sizzle
						cur.nodeType === 1 &&
							jQuery.find.matchesSelector( cur, selectors ) ) ) {

						matched.push( cur );
						break;
					}
				}
			}
		}

		return this.pushStack( matched.length > 1 ? jQuery.uniqueSort( matched ) : matched );
	},

$('#catalog>li>a').each(function(){
  $(this).html( function(i,t){
    return t.replace(/(\(\d+\))/, '<span>$1</span>')
  });
});

var data = [
  {ID: 1, country: 'England'},
  {ID: 4, country: 'USA'},
  {ID: 9, country: 'Russia'},
  {ID: 5, country: 'Germany'},
  {ID: 6, country: 'France'},
];

const order = [5,1,9,6,4];

data.sort((a,b) => order.indexOf(a.ID) - order.indexOf(b.ID));

/* [
  {"ID":5,"country":"Germany"},
  {"ID":1,"country":"England"},
  {"ID":9,"country":"Russia"},
  {"ID":6,"country":"France"},
  {"ID":4,"country":"USA"}]
*/

1. добавить в исходный массив новое поле с порядковым номером, который каждый элемент должен занять после сортировки;
   
2. отсортировать по этому полю.
   

data = data.map( e => {e.sortBy = order.indexOf(e.ID); return e;} );
data.sort( (a,b) => a.sortBy - b.sortBy);

var commons = {
  el1: document.getElementById('id1')
  ,el2: document.getElementById('id2')
  ,el3: document.getElementById('id3')
}

function A( opts ){
  opts.el1.innerHTML = 'aaa';
}

function B( opts ){
  opts.el1.innerHTML = 'A.A.A.';
  opts.el2.innerHTML = 'bbb';
  opts.el3.innerHTML = 'ccc';
}

A( commons);
B( commons);

var i, arr = ['а','б','в','г','д'];

for( i = arr.length - 1; i >= 0; i--) if( i % 2 === 1) arr.splice(i,1);
// а,в,д

function stringTween(){
  var sv = [1,2,3];
  return function(){
    sv[0] = 'a'; sv[1]='b'; sv[2]='c';
    return "string";
  }
}

stringTween();

const readline = require('readline');

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

rl.question('What do you think of Node.js? ', (answer) => {
  // здесь что-то делайте с полученной строкой answer
  console.log(`Thank you for your valuable feedback: ${answer}`);

  rl.close();
});

var result = {};
for( prop in this) {
  if( this.hasOwnProperty( prop)  &&  typeof prop != 'function') {
    result[ prop] = this[ prop];
  }
}
return result;

function findMatches( input, query) {
	query = query.split(/\s+/);
	var i, parts = [];
	for(i in query) {
		parts.push( '(?=.*(?:^|\\s)' + query[i] + ')');
	}
	
	var re = new RegExp('^' + parts.join(''), 'iug');
	
	var matches = [];
	for(i in str) {
		if( re.test( str[i])) matches.push( str[i]);
	}

	return matches;
}

var str = [
"Превед веселый медвед"
,"Медведь, тебе привет"
,"ревед веселый едвед"
,"тебе привет"
];

var query = 'Пр мед';

var result = findMatches( str, query); // ["Превед веселый медвед","Медведь, тебе привет"]