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10 Days of JavaScript

BenzhaminKim 2021. 1. 20. 21:43

Day 0: Hello, World!

1. console.log() is to print.

Day 0: Data Types

Input Format

Data TypeParameterDescription

string secondInteger The string representation of an integer you must sum with .
string secondDecimal The string representation of a floating-point number you must sum with .
string secondString A string of one or more space-separated words you must append to .

 

In order to sum with string type of number, we need to convert string to number, so we use new Number().

 

function performOperation(secondInteger, secondDecimal, secondString) {
    // Declare a variable named 'firstInteger' and initialize with integer value 4.
    const firstInteger = 4;
    
    // Declare a variable named 'firstDecimal' and initialize with floating-point value 4.0.
    const firstDecimal = 4.0;
    
    // Declare a variable named 'firstString' and initialize with the string "HackerRank".
    const firstString = 'HackerRank ';
    
    // Write code that uses console.log to print the sum of the 'firstInteger' and 'secondInteger' (converted to a Number        type) on a new line.
    console.log(firstInteger+new Number(secondInteger));
    
    // Write code that uses console.log to print the sum of 'firstDecimal' and 'secondDecimal' (converted to a Number            type) on a new line.
    console.log(firstDecimal+new Number(secondDecimal));
    
    // Write code that uses console.log to print the concatenation of 'firstString' and 'secondString' on a new line. The        variable 'firstString' must be printed first.
    console.log(firstString + secondString);
}

Day 1: Functions

For the recursive loop, you need to set the base case which is to stop the function and recurrence relation that reduces all other cases.

function factorial(n){
    if(n===0){ // base case
        return 1;
    }
    return n * factorial(n-1); // recurrence relation
}

Day 1: Let and Const

Let : you can change the variable.

Const : you cannot change the variable.

Day 2: Conditional Statements: If-Else

function getGrade(score) {
    let grade;
    // Write your code here
    if(score>25 && score< 30){
        grade = 'A';
    }
    else if(score > 20 && score <=25){
        grade = 'B';
    }
    else if(score > 15 && score <=20){
        grade = 'C';
    }
    else if(score > 10 && score <=15){
        grade = 'D';
    }
    else if(score > 5 && score <=10){
        grade = 'E';
    }
    else if(score > 0 && score <=5){
        grade = 'F';
    }
    return grade;
}

Day 2: Loops

function vowelsAndConsonants(s) {
    let vowels = ["a", "e", "i", "o", "u"];

    for(let v of s) {
        if(vowels.includes(v))
            console.log(v);
    }
    
    for(let v of s) {
        if(!vowels.includes(v))
            console.log(v);
    }
}

function vowelsAndConsonants(s) {
    for(let i=0; i<s.length; i++){
        if(s[i] === 'a' ||s[i] === 'e' ||s[i] === 'i' ||s[i] === 'o' ||s[i] === 'u'){
            console.log(s[i]);   
        }
    }
    for(let i=0; i<s.length; i++){
        if(s[i] !== 'a' && s[i] !== 'e' && s[i] !== 'i' && s[i] !== 'o' && s[i] !== 'u'){
            console.log(s[i]);   
        }
    }
}

Day 3: Arrays

let fruits = ['Apple', 'Banana']

let newLength = fruits.push('Orange')
// ["Apple", "Banana", "Orange"]

let last = fruits.pop() // remove Orange (from the end)
// ["Apple", "Banana"]

let first = fruits.shift() // remove Apple from the front
// ["Banana"]

let newLength = fruits.unshift('Strawberry') // add to the front
// ["Strawberry", "Banana"]

 

Day 4: Classes

'use strict';

function Fruit (type) {
    this.type = type;
    this.color = 'unknown';
    this.getInformation = function() {
        return 'This ' + this.type + ' is ' + this.color + '.';
    }
}

let lime = new Fruit('Mexican lime');
console.log(lime.getInformation());

lime.color = 'green';
console.log(lime.getInformation());
'use strict';

function Fruit (type) {
    this.type = type;
    this.color = 'unknown';
}

Fruit.prototype.getInformation = function() {
    return 'This ' + this.type + ' is ' + this.color + '.';
}

let lime = new Fruit('Mexican lime');
console.log(lime.getInformation());

lime.color = 'green';
console.log(lime.getInformation());