Добро пожаловать на канал "JavaScript test"! Здесь вы сможете проверить свои знания по языку JavaScript и узнать новые интересные факты. Мы предлагаем тесты, задачи и практические упражнения, которые помогут вам улучшить свои навыки программирования на JavaScript.
Присоединяйтесь к нашему каналу и станьте экспертом в JavaScript! Ссылка на наш партнерский канал: @Portal_v_IT.
Если у вас есть предложения по сотрудничеству или вопросы, не стесняйтесь обращаться к администраторам: @oleginc, @tatiana_inc.
Не упустите возможность улучшить свои навыки программирования на JavaScript! Присоединяйтесь к каналу "JavaScript test" уже сегодня!
Ссылка на канал на бирже: [https://telega.in/c/js_test]
20 Feb, 08:21
const numbers = [1, 2, 3, 4, 5];
const result = numbers
.filter(num => num % 2 === 0)
.map(num => num * num)
.reduce((acc, num) => acc + num, 0);
console.log(result);
19 Feb, 16:12
var a=[1,2,3,4,5];
console.log(a.some(x=>x>4));
console.log(a.some(x=>x>5));
19 Feb, 14:07
19 Feb, 11:07
let person = {
name: 'Alice',
age: 30,
valueOf: function() {
return this.age;
}
};
let result = person + 10;
console.log(result);18 Feb, 16:13
function removeOdd(arr){
//remove odd number of arr
for (var i=arr.length;i>=0;i--)
if (arr[i]%2) arr.splice(i,1)
return arr;
}
console.log(removeOdd([1,2,3,4,5]))
console.log(removeOdd([1,3,5,7,9]))18 Feb, 14:07
18 Feb, 08:07
const obj1 = { a: 1, b: 2 };
const obj2 = { b: 3, c: 4 };
const mergedObj = { ...obj1, ...obj2 };
console.log(mergedObj);17 Feb, 16:08
var names=["John","Tom","Jerry","Minne","Alice","othername..."];
for (var i=0;i<5;i++)
console.log(names[~~(names.length*Math.random())]);
17 Feb, 11:08
var data=[1,2,3,4,5];
var filterData=a.filter(function(x){return x<=5});
console.log(filterData);
17 Feb, 09:10
17 Feb, 09:03
function Person(name, age) {
this.name = name;
this.age = age;
}
Person.prototype.getDetails = function() {
return this.name + ' is ' + this.age + ' years old.';
};
const john = new Person('John', 25);
console.log(john.getDetails());16 Feb, 16:08
let weakmap = new WeakMap();
let obj1 = {};
let obj2 = {};
weakmap.set(obj1, 'value1');
weakmap.set(obj2, 'value2');
obj1 = null;
console.log(weakmap.has(obj1));
16 Feb, 14:07
16 Feb, 11:07
function multiply(a, b) {
if (b === 0) {
return 0;
} else if (b > 0) {
return a + multiply(a, b - 1);
} else {
return -multiply(a, -b);
}
}
console.log(multiply(300, 0));16 Feb, 09:07
16 Feb, 08:07
const obj1 = {
a: 1,
method() {
return this.a;
}
};
const obj2 = Object.create(obj1);
obj2.a = 777;
console.log(obj2.method());15 Feb, 16:10
const promise = new Promise((resolve, reject) => {
reject('Error occurred');
});
promise
.then(() => {
console.log('Promise resolved!');
})
.catch(error => {
console.log(error);
})
.then(() => {
console.log('Process completed');
});15 Feb, 11:07
var arr=[[9,0],[5,3],[2,6],[7,8]];
var result=[];
for (var i=0;i<arr.length;i++)
result=result.concat(arr[i]);
console.log(result.sort());
15 Feb, 10:52
15 Feb, 08:07
var arr=[[9,0],[5,3],[2,6],[7,8]];
var result=[];
for (var i=0;i<arr.length;i++)
result=result.concat(arr[i]);
console.log(result);
14 Feb, 16:09
function rndnum(from,to){
return ~~((to-from)*Math.random()+from);
}
for (var i=0;i<5;i++) console.log(rndnum(20,30));14 Feb, 14:07
14 Feb, 08:50
function outerFunction() {
let x = 10;
function innerFunction() {
x += 5;
console.log(x);
}
return innerFunction;
}
const closureFunc = outerFunction();
closureFunc();
closureFunc();13 Feb, 16:53
var arr=[1,2,3,4,5];
console.log(arr.join());
console.log(arr.join(","));
console.log(arr.join(" "));
console.log(arr.join("and"));
13 Feb, 11:08
function recursivePascalTriangle(n, row = [1], triangle = []) {
triangle.push(row);
if (n === triangle.length) {
return triangle;
}
const nextRow = [1];
for (let i = 1; i < row.length; i++) {
nextRow.push(row[i] + row[i - 1]);
}
nextRow.push(1);
return recursivePascalTriangle(n, nextRow, triangle);
}
const result = recursivePascalTriangle(5);
console.log(result);13 Feb, 08:30
const symbol1 = Symbol('symbol');
const symbol2 = Symbol('symbol');
const obj = {};
obj[symbol1] = 'value1';
obj[symbol2] = 'value2';
console.log(obj[symbol1]);12 Feb, 11:07
function* numberGenerator() {
yield 1;
yield 2;
yield 3;
}
const gen = numberGenerator();
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next().value);11 Feb, 16:24
var str="My".concat("name","is","John");
console.log(str);11 Feb, 11:08
let obj = { a: 1 };
Object.freeze(obj);
console.log(Object.isFrozen(obj));
console.log(obj.a = 2);
console.log(obj.a);11 Feb, 08:15
'use strict';
function strictModeExample() {
undeclaredVariable = 10;
try {
console.log(undeclaredVariable);
} catch (e) {
console.log('Error:', e.message);
}
}
strictModeExample();
10 Feb, 16:32
var str="example";
var result=str.replace("e","@");
console.log(result);
10 Feb, 11:12
console.log(Math.round(1.45));
console.log(Math.ceil(1.45));
console.log(Math.floor(1.45));
console.log(Math.round(1.55));
console.log(Math.ceil(1.55));
console.log(Math.floor(1.55));
10 Feb, 08:44
let a = 5;
let b = a++ + ++a;
console.log(b);
09 Feb, 16:24
const a = '5';
const b = 5;
const c = 10;
const result1 = a == b;
const result2 = a === b;
const result3 = b < c;
const result4 = b >= c;
console.log(result1, result2, result3, result4);
09 Feb, 11:07
function addCommas(money){
var re=/\d{3}(?!$)/g
return money.replace(re,x=>x+",")
}
console.log( addCommas("$123456789") )
console.log( addCommas("$123456") )
console.log( addCommas("$1234567890") )
console.log( addCommas("$1234567") )09 Feb, 08:06
var str="javascript coffeescript vbscript javacode"
var re2=/(?=java)\b\w+script\b/g
console.log(str.match(re2))
var str="dog,cat,pig,cow"
var re2=/\b\w+\b(?=,cat|,pig)/g
console.log(str.match(re2))
08 Feb, 16:08
const person = {
firstName: 'John',
lastName: 'Doe',
age: 30,
getFullName: function() {
return this.firstName + ' ' + this.lastName;
}
};
console.log(person.getFullName());08 Feb, 15:25
08 Feb, 11:07
function addCommas(money){
var re=/\d{3}(?!$)/g
return money.replace(re,x=>x+",")
}
console.log( addCommas("$123456789") )08 Feb, 08:07
function addCommas(money){
var re=/\d{3}/g
return money.replace(re,x=>x+",")
}
console.log( addCommas("$123456789") )07 Feb, 17:09
function verify(username){
return /^[a-z][a-z0-9_]{5,15}$/i.test(username);
}
console.log( verify("myjinxin2015"))
console.log( verify("smile67"))
console.log( verify("GiacomoSorbi"))
console.log( verify("jhoffner"))
console.log( verify("g964") )
console.log( verify("matt c") ) /
console.log( verify("My_name_is_ZozoFouchtra") )06 Feb, 11:07
var str="abba baab green glass roof";
var reg=/(.)(.)\2\1/g
console.log( str.match(reg))
06 Feb, 08:16
const person = {
name: 'Alice',
age: 25,
city: 'Wonderland'
};
const additionalInfo = {
age: 30,
occupation: 'Explorer'
};
const combined = {
...person,
...additionalInfo
};
console.log(combined.age);05 Feb, 17:23
var str="dog,cat,pig,cow"
var re1=/\b\w+\b/g
var re2=/\b\w+\b(?=,cat|,pig)/g
var re3=/\b\w+\b(?!,cat|,pig)/g
var re4=/(?=c)\b\w+\b(?!,cat|,pig)/g
console.log( str.match(re1))
console.log( str.match(re2))
console.log( str.match(re3))
console.log( str.match(re4))
05 Feb, 08:10
const numbers = [1, 2, 3, 4, 5];
const result = numbers
.filter(n => n % 2 === 0)
.map(n => n * 2)
.reduce((acc, n) => acc + n, 0);
console.log(result);
04 Feb, 16:11
var str="javascript coffeescript vbscript javacode"
var re1=/\b\w+script\b/g
var re2=/(?=java)\b\w+script\b/g
var re3=/(?!java)\b\w+script\b/g
console.log( str.match(re1))
console.log( str.match(re2))
console.log( str.match(re3))
04 Feb, 11:08
var reg2=/^a..$/
console.log(reg2.test("abc"))
console.log(reg2.test("bbc"))
console.log(reg2.test("abcd"))
04 Feb, 08:16
const wm = new WeakMap();
const obj1 = {};
const obj2 = {};
wm.set(obj1, 'object 1');
wm.set(obj2, 'object 2');
wm.delete(obj1);
console.log(wm.has(obj1));
03 Feb, 18:04
var str="a1!b2@c3#d4$e5%";
console.log( str.replace(/[^a-z]/g,""))
console.log( str.replace(/[^0-9]/g,""))
console.log( str.replace(/[^!@#$%]/g,""))
03 Feb, 11:24
var s="100001,111,12222221,222,3333,12321,14441";
var match1=s.match(/1.*1/g)
var match2=s.match(/1.+1/g)
console.log(match1)
console.log(match2)
27 Jan, 16:08
var chars="abcde".split("");
for (var i=0;i<chars.length;i++){
var tmp=chars[i].charCodeAt();
if (tmp==97) console.log("a for apple");
else console.log(tmp);
}27 Jan, 11:07
var str="Hello World!";
console.log(str.indexOf("world"))
console.log(str.lastIndexOf("world"))
console.log(str.search(/world/i))
console.log(str.search(/word/i))
27 Jan, 08:17
let arr = [1, 2, 3, 4, 5];
arr.length = 3;
console.log(arr.length);
console.log(arr);
26 Jan, 16:07
var str=" a b c ";
console.log(str.trim());
26 Jan, 14:07
26 Jan, 11:07
let arr = [1, 2, 3, 4, 5];
arr.length = 3;
arr.push(6, 7);
console.log(arr.length);
26 Jan, 08:07
var num=111.1234;
var s=num.toFixed(2) //s=="111.12"
var a=parseInt(s),
b=parseFloat(s),
c= +s
console.log([a,b,c])
25 Jan, 18:18
function isPair(s){
var r=/\(\)|\[\]|\{\}/g;
while (r.test(s)) s=s.replace(r,"");
return s=="";
}
console.log( isPair(")()(") )
console.log( isPair(")(") )
console.log( isPair("({[})") )25 Jan, 11:07
var n=1.23456
var a=Math.round(n*100)/100
var b=Math.ceil(n*100)/100
var c=Math.floor(n*100)/100
console.log(a,b,c);
25 Jan, 08:07
var words=["abc","123","&##"];
const students = [
{ name: 'Alice', age: 20 },
{ name: 'Bob', age: 22 },
{ name: 'Charlie', age: 23 }
];
const studentToFind = { name: 'Bob', age: 22 };
const isIncluded = students.includes(studentToFind);
console.log(isIncluded);
24 Jan, 16:36
var words=["abc","123","&##"];
for (var r of words){
var reg=new RegExp(r)
console.log(reg)
}
24 Jan, 11:07
var word="abcd";
var regstr=word[0]+Array(word.length-1).join(".")+word.slice(-1);
var reg3=new RegExp("^"+regstr+"$");
console.log(reg3)
24 Jan, 08:20
const numbers = [10, 23, 45, 60, 78];
const isDivisibleByFive = numbers.some(num => num % 5 === 0);
if (isDivisibleByFive) {
console.log('Some numbers are divisible by 5');
} else {
console.log('No numbers are divisible by 5');
}
23 Jan, 16:08
var reg2=/^a.c$/
console.log(reg2.test("abc"))
console.log(reg2.test("abd"))
console.log(reg2.test("abbc"))
23 Jan, 11:07
function aAn(word){
return (/^(a|e|i|o|u)/i.test(word) ? "An " : "A ") + word;
}
console.log( aAn("apple")) 23 Jan, 08:11
const numbers = [2, 4, 6, 8, 10];
const allEven = numbers.every(function(num) {
return num % 2 === 0;
});
console.log(allEven);
22 Jan, 16:18
var str="good wood food cat bat hat";
console.log( str.match(/(g|w|f)ood/g) );
22 Jan, 11:10
function isPair(s){
var r=/\(\)|\[\]|\{\}/g;
while (r.test(s)) s=s.replace(r,"");
return s=="";
}
console.log( isPair("()") )
console.log( isPair("((()))") )
console.log( isPair("({[]})") )22 Jan, 08:28
var obj = {
a: 10,
b: 20
};
with (obj) {
var result = a + b;
}
console.log(result);21 Jan, 17:34
var regex=/[*+?.|()]/g;
console.log( "(a*b+c?)|(.)".match(regex) );
18 Jan, 16:09
var s="100001,111,12222221,222,3333,12321,14441";
var match=s.match(/1.+?1/g)
console.log(match)
18 Jan, 14:12
18 Jan, 11:07
var s="aaaabbbb";
console.log( s.match(/a*b/)+"" );
console.log( s.match(/a*b*/)+"" );
18 Jan, 08:06
var s="ab";
console.log( /a?b/.test(s) );
console.log( /x?b/.test(s) );
console.log( /x?b?/.test(s) );
console.log( /x?y?/.test(s) );
17 Jan, 16:08
function intRoot1(n){
return Number.isInteger(Math.sqrt(n));
}
function intRoot2(n){
return Math.sqrt(n)%1==0;
}
function intRoot3(n){
var x=Math.round(Math.sqrt(n));
return x*x==n;
}
console.log(intRoot1(16))
console.log(intRoot2(16))
console.log(intRoot3(16)) 17 Jan, 12:37
function removeOdd(arr){
for (var i=0;i<arr.length;i++)
if (arr[i]%2) arr.splice(i,1)
return arr;
}
console.log(removeOdd([1,3,5,7,9])) 17 Jan, 08:11
var word="abcd";
var regstr=word[0]
+word.slice(1,-1).replace(/./g,".")
+word.slice(-1);
var reg1=new RegExp("^"+regstr+"$");
console.log(reg1)
16 Jan, 17:58
var a=[1,2,3,4,5];
var b=a.filter(x=>x%2);
console.log(b);
16 Jan, 11:47
function capIt(str){
return str.split(/ /)
.map(s=>s.replace(/^./,x=>x.toUpperCase()))
.join(" ")
}
console.log( capIt("hello world!"))
console.log( capIt("my name is John."))16 Jan, 08:07
const a = '10';
const b = 20;
const c = '30.5';
const result = Number(a) + b + Number.parseFloat(c);
console.log(result);
15 Jan, 16:08
var str="aaaabbbb";
console.log( str.match(/a{0,0}b/)+"" );
console.log( str.match(/a{0,1}b/)+"" );
console.log( str.match(/a{0,2}b/)+"" );
console.log( str.match(/a{0,100}b/)+"" );
15 Jan, 11:10
var str="abcdef";
console.log( str.match(/./g) )
console.log( str.match(/../g) )
console.log( str.match(/.../g) )
15 Jan, 09:02
let str = "Hello, World!";
let result = str.substring(7, 12);
console.log(result);
14 Jan, 16:39
var str="Hello beautiful World!";
console.log(str.slice(16,21))
console.log(str.substring(16,21))
console.log(str.slice(16,-1))
14 Jan, 11:07
function decode(str){
var chars=str.split("");
for (var i=0;i<chars.length;i++)
chars[i]=String.fromCharCode(chars[i].charCodeAt()-1);
return chars.join("");
}
function encode(str){
var chars=str.split("");
for (var i=0;i<chars.length;i++)
chars[i]=String.fromCharCode(chars[i].charCodeAt()+1);
return chars.join("");
}
var s="abcde"
s=encode(s);
console.log("encode:",s)
s=decode(s);
console.log("decode:",s)14 Jan, 08:10
function displayArguments() {
console.log(arguments.length);
console.log(arguments[0]);
console.log(arguments[2]);
}
displayArguments('Hello', 'World', 'JavaScript', 'Quiz');13 Jan, 16:08
var str="My name is John";
var words=str.split("");
console.log(words);
13 Jan, 11:07
function trickyFunction() {
let a = 5;
let b = '5';
let c = 5;
if (a == b && b === c) {
console.log('Condition 1');
} else if (a === c || b == c) {
console.log('Condition 2');
} else {
console.log('Condition 3');
}
}
trickyFunction();13 Jan, 08:07
var obj = { a: 10, b: 20 };
with (obj) {
var result = a + b;
}
console.log(result);12 Jan, 16:08
const myObject = {
a: 1,
b: 2,
c: 3,
[Symbol.iterator]: function* () {
for (let key of Object.keys(this)) {
yield this[key];
}
}
};
const iter = myObject[Symbol.iterator]();
console.log(iter.next().value);
console.log(iter.next().value);
console.log(iter.next().value);12 Jan, 12:17
function* customGenerator() {
yield 'Hello';
yield 'World';
return 'Done';
}
const gen = customGenerator();
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next().value);12 Jan, 10:16
12 Jan, 08:15
const mySet = new Set();
mySet.add(10);
mySet.add(20);
mySet.add(10);
mySet.add(30);
console.log(mySet.size);
11 Jan, 16:07
const WM = new WeakMap();
let obj = {};
let anotherObj = {};
WM.set(obj, 'object data');
WM.set(anotherObj, 'another object data');
obj = null;
console.log(WM.has(obj));
console.log(WM.has(anotherObj));
11 Jan, 11:07
async function fetchData() {
let data = 'initial';
const promise = new Promise((resolve) => {
setTimeout(() => {
resolve('fetched');
}, 1000);
});
promise.then((result) => {
data = result;
});
return data;
}
fetchData().then(console.log);11 Jan, 08:07
function trickyFunction() {
var obj = { a: 1 };
var anotherObj = obj;
obj.a = 2;
obj = { a: 3 };
anotherObj.a = 4;
return obj.a + anotherObj.a;
}
console.log(trickyFunction());10 Jan, 16:22
function trickyFunction() {
var x = 10;
if (x > 5) {
let y = x * 2;
x = y;
}
return x;
}
console.log(trickyFunction());10 Jan, 12:22
function trickyFunction() {
var a = 10;
var b = a;
b = 15;
const obj1 = { x: 1 };
const obj2 = obj1;
obj2.x = 5;
console.log(a + ' ' + b + ' ' + obj1.x);
}
trickyFunction();10 Jan, 08:09
const obj = {
valueOf() {
return 42;
}
};
const result = obj + 8;
console.log(result);09 Jan, 16:07
var chars=[];
for (var i=97;i<123;i++){
chars.push(String.fromCharCode(i));
}
console.log(chars.join(""))
09 Jan, 14:10
09 Jan, 11:07
function combine(...arrays) {
return arrays.reduce((acc, arr) => [...acc, ...arr], []);
}
const result = combine([1, 2], [3, 4], [5, 6]);
console.log(result);09 Jan, 09:07
09 Jan, 08:06
var arr1=[1,2,3,4,5];
var arr2=[6,7,8,9,10];
var result=arr1.map(x=>x*x).reduce((a,b,i,ar)=>a.concat(ar[i],arr2[i]),[])
console.log(result);
08 Jan, 16:07
var arr=[1,2,3,4,5];
console.log(arr.reduce((a,b)=>a+(b%2?1:0),0));
console.log(arr.reduce((a,b)=>a+(b%2?0:1),0));
08 Jan, 14:07
08 Jan, 11:07
function average(arr){
return arr.reduce((a,b)=>a+b)/arr.length
}
console.log(average([1,2,3,4,5]));08 Jan, 09:06
08 Jan, 08:06
var arr=[1,2,3,4,5];
console.log(arr.reduce((a,b)=>a+b,""));
07 Jan, 16:07
var arr=[1,2,3,4,5];
console.log(arr.reduce((prev,curr)=>prev+curr));
console.log(arr.reduce((a,b)=>a+b));
07 Jan, 11:06
var year1=Math.log1p(0.2)/Math.log1p(0.1)
console.log(year1)
var year2=Math.log1p(0.5)/Math.log1p(0.1)
console.log(year2)
var year3=Math.log1p(0.8)/Math.log1p(0.1)
console.log(year3)
console.log(Math.ceil(year1),Math.ceil(year2),Math.ceil(year3))
var year4=Math.log1p(9)/Math.log1p(0.1)
console.log(Math.ceil(year4))
07 Jan, 08:06
var base=2,n1=4,n2=1024,n3=1048576
console.log( Math.log(n1)/Math.log(base) )
console.log( Math.log(n1)/Math.LN2 )
console.log( Math.log(n2)/Math.log(base) )
console.log( Math.log(n3)/Math.log(base) )
console.log(Math.pow(base,2))
console.log(Math.pow(base,10))
console.log(Math.pow(base,20))
06 Jan, 16:07
var arr=[1,2,3,4,5];
console.log(arr.toString());
console.log(arr+"");
console.log(arr.join());
06 Jan, 11:07
var arr=[1,2,3,4,5];
console.log(arr.indexOf(1));
console.log(arr.indexOf(5));
console.log(arr.indexOf(6));
06 Jan, 09:15
06 Jan, 08:06
var a=[1], b=1, c="1", d={1:1}
console.log(Array.isArray(a));
console.log(Array.isArray(b));
console.log(Array.isArray(c));
console.log(Array.isArray(d));
console.log(Array.isArray(e));05 Jan, 16:48
var n=64;
console.log(Math.sqrt(n));
console.log(Math.pow(n,0.5));
console.log(Math.pow(n,1/2));
console.log(Math.cbrt(n));
console.log(Math.pow(n,0.333333333333333333));
console.log(Math.pow(n,1/3));
05 Jan, 11:07
var n=2
console.log(Math.pow(n,2));
console.log(n*n);
console.log(n**2);
console.log(Math.pow(n,3));
console.log(n*n*n);
console.log(n**3);
05 Jan, 08:06
var arr1=[1,4,9];
var sqroot=arr1.map(Math.sqrt);
console.log(sqroot);
var arr2=[1,8,27];
var cbroot=arr2.map(Math.cbrt);
console.log(cbroot);
var arr3=[1,2,3];
var pow2=arr3.map(x=>Math.pow(x,2));
var pow3=arr3.map(x=>Math.pow(x,3));
console.log(pow2);
console.log(pow3);
04 Jan, 16:08
var str="this is an example.";
var words=str.split(" ");
for (var i=0;i<words.length;i++){
words[i]=words[i].replace(words[i][0],words[i][0].toUpperCase());
}
console.log(words.join(" "));
04 Jan, 11:07
var str="this is an example.";
var words=str.split(" ");
for (var i=0;i<words.length;i++){
words[i]=words[i][0].toUpperCase()+words[i].slice(1);
}
console.log(words.join(" "));
04 Jan, 08:07
var str="My name is John";
console.log(str.toUpperCase());
console.log(str.toLowerCase());
03 Jan, 16:07
var a=[...Array(4)]
var b=a.map((_,i)=>i)
var c=[...Array(4)].map((_,i)=>i)
var d=Array.prototype.map.call(a,(_,i)=>i)
console.log(a)
console.log(b)
console.log(c)
console.log(d)
03 Jan, 11:07
var a=[1,2,3,4]
var b=a.map(x=>x+1)
console.log(a)
console.log(b)
03 Jan, 08:07
var a=[1,4,9,16]
var b=a.map(Math.sqrt)
console.log(a)
console.log(b)
02 Jan, 16:07
var str="abcde";
for (var i=0;i<str.length;i++){
console.log(str.charAt(i),str.charCodeAt(i));
}
02 Jan, 11:08
var str="abcde";
console.log(str[0]);
console.log(str[1]);
02 Jan, 08:06
var str="abcde";
console.log(str.charAt(0));
console.log(str.charAt(1));
01 Jan, 16:07
var a=[3,6,9,12,24,36]
var b=a.filter(x=>x%2==0&&x%3==0&&x%4==0)
console.log(b)
27 Dec, 16:08
function repeat(s,n){
return [...Array(n+1)].join(s);
}
console.log(repeat("a",5));
console.log(repeat("abc",5));27 Dec, 14:07
27 Dec, 11:18
var arr=[[1,2],[3,4],[5,6]];
var result=[].concat(...arr);
console.log(result);
27 Dec, 09:07
27 Dec, 08:16
var num=111;
var a=num.toString(2),
b=num.toString(8),
c=num.toString(16),
console.log([a,b,c])
26 Dec, 17:07
var arr=[1,2,3,11,21,31];
arr.sort((a,b)=>a-b);
console.log(arr)
arr.sort((a,b)=>b-a);
console.log(arr)
26 Dec, 15:50
26 Dec, 11:07
var str="My name is John";
var words1=str.split(" ",3);
console.log("words1:",words1);
var words2=str.split(" ",5);
console.log("words2:",words2);
26 Dec, 09:07
26 Dec, 08:07
var arr1=[1,2,3],arr2=[4,5,6];
console.log(arr1.concat(arr2));
console.log(arr1.concat(4,5,6));
console.log(arr1.concat([4],[5],[6]));
console.log(arr1.concat(...arr2));
console.log(arr1.concat(4).concat(5).concat(6));
25 Dec, 16:06
function sum1_100(){
var sum=0,num=1;
do{
sum+=num;
num++;
}while (num<=100)
return sum;
}
console.log(sum1_100()) 25 Dec, 11:11
var arr1=["1","2","3","4","5"];
console.log(arr1.toString());
console.log(JSON.stringify(arr1));
25 Dec, 08:07
var pushElement=(arr,el1,el2)=>{
arr.push(el1);
arr.push(el2);
return arr;
}
console.log( pushElement([1],2,3) );24 Dec, 17:02
var arr=[1,2,3,11,21,31];
arr.sort();
console.log(arr)
24 Dec, 11:10
var a=0,b=0,arr=[3,6,9,6,9,3];
arr.some((x,i)=>{
a=arr[i]; //or a=x
b=arr[i+1];
return a+b==15
})
console.log(a,b)
24 Dec, 08:17
var a=[1,2,3,4,5];
a.every(x=>{
console.log(x);
return x<4;
})
23 Dec, 16:06
var str="Hello beautiful World!";
console.log(str.slice(6,16))
console.log(str.substring(6,16))
console.log(str.substr(6,9))
23 Dec, 11:07
const variable = () => {
console.log(arguments);
}
variable([1]);22 Dec, 16:07
var arr1=["1","2","3","4","5"];
console.log(arr1.toString());
console.log(JSON.stringify(arr1));
var arr2=[[1,2],[3,4],[5]];
console.log(arr2.toString());
console.log(JSON.stringify(arr2));
22 Dec, 11:07
var str="this is an example.";
var result=str[0].toUpperCase()+str.slice(1);
console.log(result);
30 Nov, 08:07
const regex = /colou?r/;
console.log(regex.test('color'), regex.test('colour'), regex.test('colr'));
29 Nov, 16:07
const regex = /(?<day>\d{2})-(?<month>\d{2})-(?<year>\d{4})/;
const str = '25-12-2020';
const { groups: { day, month, year } } = str.match(regex);
console.log(day, month, year);29 Nov, 11:07
function processData({ a = 10, b = 20 } = { a: 30 }) {
console.log(a, b);
}
processData({ a: 5 });
processData();29 Nov, 10:34
29 Nov, 08:56
const arr = [1, 2];
arr.length = 0;
console.log(arr[0]);
28 Nov, 16:07
const regex = /\d{2,}/;
console.log(regex.test('5'), regex.test('55'), regex.test('555'));28 Nov, 12:37
const arr = [...new Set([3, 1, 2, 3, 4])]
console.log(arr.length, arr[2])
28 Nov, 08:42
const obj = {};
Object.defineProperty(obj, "prop", {
value: 42,
writable: false
});
obj.prop = 100;
console.log(obj.prop);27 Nov, 16:11
let javascript_tests = 1000
try {
javascript_tests = 550
} finally {
javascript_tests = 64
}
console.log(javascript_tests)
27 Nov, 11:07
const regex = /\bcat\b/;
console.log(regex.test('concatenate'), regex.test('cat'), regex.test('scatter'));
27 Nov, 08:07
const x = (() => {
try {
return 10;
} finally {
return 20;
}
})();
console.log(x);26 Nov, 16:07
const regex = /\D+/;
const str = '123abc456';
console.log(str.match(regex)[0]);
26 Nov, 08:07
const arr = [1, 2, 3];
arr[-1] = 10;
console.log(arr.length, arr[-1]);
25 Nov, 16:07
const regex = /^cat/gm;
const str = `dog
cat
bat`;
console.log(str.match(regex));
25 Nov, 11:07
const parent = { name: 'John' };
const child = Object.create(parent);
child.age = 5;Object.create() позволяет создать новый объект, который наследует свойства и методы от родительского объекта parent.25 Nov, 08:42
const regex = /ba{2,3}n/;
console.log(regex.test('ban'), regex.test('baan'), regex.test('baaan'));24 Nov, 16:07
const set = new Set([1, 1, 2, 3, 4]);
console.log(set);
24 Nov, 11:07
const regex = /(foo)(bar)/;
const str = 'foobar';
const match = str.match(regex);
console.log(match[0], match[1], match[2]);
24 Nov, 08:07
const regex = /<.*?>/;
const str = '<div>Content</div>';
console.log(str.match(regex)[0]);
23 Nov, 16:07
const regex = /a/g;
const str = 'banana';
console.log(str.match(regex));
23 Nov, 11:06
try {
throw new Error('Ошибка!');
} catch (e) {
console.log(e.message);
} finally {
console.log('Finally выполнен');
}23 Nov, 09:13
23 Nov, 08:07
Promise.resolve для создания успешного промисаPromise.resolve создает успешный промис с указанным значением.const resolvePromise =
Promise.resolve('Успешное выполнение');
resolvedPromise.then(result => {
console.log(result);
});
22 Nov, 16:07
async function test() {
return await Promise.resolve('Привет');
}
test().then(console.log);22 Nov, 11:07
const arr = [1, 2, 3];
const str = arr.join('');
console.log(typeof str);
console.log(str);
22 Nov, 08:25
const obj = {
valueOf: () => 42,
toString: () => "Hello"
};
console.log(`${obj}`, obj + 10);21 Nov, 16:07
class Animal {
constructor(name) {
this.name = name;
}
speak() {
console.log(`${this.name} издает звук.`};
}
}
class Dog extends Animal {
speak() {
console.log(`${this.name} лает.`};
}
}
const dog = new Dog('Барсик');
dog.speak(); 21 Nov, 11:07
const a = {};
const b = {};
console.log(a == b);
console.log(a === b);21 Nov, 09:11
21 Nov, 08:36
const arr = [1, 2, 3];
arr[10] = 4;
console.log(arr.length);
20 Nov, 16:07
function getItems(fruitList, ...args, favoriteFruit) {
return [...fruitList, ...args, favoriteFruit]
}
getItems(["banana", "apple"], "pear", "orange")20 Nov, 14:07
20 Nov, 11:07
var x = 5;
(function() {
console.log(x);
var x = 10;
console.log(x);
})();
20 Nov, 08:17
let i = 0;
const arr = new Array(5);
arr.forEach(() => i++);
console.log(i);
19 Nov, 16:37
var a = 1;
function f() {
console.log(a);
var a = 5;
}
f();
19 Nov, 11:46
const x = [1, 2, 3, 4, 5];
console.log(x.slice(1, 3));
19 Nov, 08:07
const numbers = [1, 2, 3, 4, 5];
const sum = numbers.reduce((acc, current) => acc + current, 10);
console.log(sum);
18 Nov, 16:07
const set = new Set([1, 2, 3, 4, 5, 6]);
const iterator = set[Symbol.iterator]();
let total = 0;
for (const num of iterator) {
if (num % 2 === 0) {
total += num;
}
}
console.log(total);
18 Nov, 14:36
git init, git add, git commit, git branch и другие. 18 Nov, 09:07
17 Nov, 09:50
14 Nov, 09:07
13 Nov, 14:07
13 Nov, 09:48
03 Nov, 14:07
02 Nov, 15:18
27 Oct, 10:34
26 Oct, 14:07
25 Oct, 14:34
25 Oct, 09:07
24 Oct, 14:07
22 Oct, 14:07
22 Oct, 10:11
21 Oct, 14:14
21 Oct, 09:07
20 Oct, 14:14
19 Oct, 14:07
15 Oct, 14:16
