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'use strict'; JavaScript is synchronous. (동기적_작성순서에 따름) Execute the code block by orger after hoisting. hoisting: var, function declaration (함수 선언들이 자동적으로 가장 위로 올라감 / 코드순서대로 실행) console.log('1'); //1 //지정한 시간이 지나면 callback함수 호출 setTimeout(function(){ console.log('2'); },1000);//1초 후 browser가 출력 //간략히 setTimeout(()=> console.log('2'),1000); console.log('3'); //1,3,2 Synchronous callback function ..

HTTP: hyperText Transfer Protocol _ client와 server의 소통 AJAX( Asynchronous JavaScript And XML ) - XHR( XMLHttpRequest ): 브라우저 api obj, 서버에 data요청, 수령 - fetch() API (ie X) - JSON( JavaScript Object Notation ): ECMAScript 3rd 1999 에서 영감을 받아 생성됨 - Object( key; value } - simplest data interchange format - lightweight text-based struncture - easy to read - key-value pairs - used for serialization and ..

Q1. make a string out of an array { const fruits = ['apple', 'banana', 'orange']; const resule = fruits.join(); console.log(result); //apple.banana,orange const resule = fruits.join('^'); //구분자 추가 console.log(result); //apple^banana^orange } Q2. make an array out of a string { const fruits = '🍎, 🥝, 🍌, 🍒'; const result = fruits.split(','); //구분자 전달하기(필수) console.log(result); //["🍎","🥝","🍌","🍒"] c..

JS = dynamically typed language 1. Declaration const arr1 = new Array(); const arr2 = [1,2]; 2. Index position const fruits = ['🍎','🍌']; console.log(fruits);//['🍎','']; console.log(fruits.length);//2 console.log(fruits['key']);//key에 상응하는 value 받음 console.log(fruits[0]);//🍎 console.log(fruits[1]);//🍌 console.log(fruits[2]);//undefined console.log(fruits[fruits.length-1]);//마지막 요소 console.clear()..

one of the JS's data types a collection of related data and/or functionality. Nearly all objects in JS are instances of Object. object = {key:value}; const name = 'ellie'; const age= 4; print(name, age); function print(name, age) { console.log(name); console.log(age); } //간략히 function print(person) { console.log(person.name); console.log(person.age); } const ellie = {name: 'ellie', age: 4}; prin..

'use strict' class person{ name; age;//속성(field) speak();//행동(method) } class = fields + methods class: template / declare once / no data in ex) 붕어빵틀 object: instance of a class / created many times / data in ex) 팥붕어빵, 슈크림붕어빵 object-oriented programming class: template object: instance of a class javascript classes - introduced in ES6 - syntactical sugar over prototype-based inheritance 1. Class..

Function - fundamental building block in the program - subprogram can be used multiple times - performs a task or calculates a value 1. Function declaration - function name(param1, param2) {body.. return;} - one function === one thing - naming: doSomething, command, verb ex) createCardAndPoint -> createdcard, createPoint - function is object in JS_ 변수할당가능, parameter전달, function return o function..

1. String concatenation console.log('my'+'cat'); console.log('1'+2); console.log(`string literals: 1 +2 = ${1 + 2}`); string literals 장점_ 줄바꿈이나 중간에 ''를 이용해도 그대로 문자열로 변환됨 (＼' : 문자열 ＼n : 줄바꿈 ＼t : tab) 2. Numeric operators console.log(1+1);//add console.log(1-1);//substract console.log(1*1); //multiply console.log(1/1); //divide console.log(1%1); //remainder console.log(1**1); //exponentiation 3. I..

1. Use strict added in ES 5 use this for Vanila Javascript. 'use strict'; 2. Variable, rw(read/write) let (added in ES6) let globalName = 'global name'; { let name = 'ellie'; console.log(name); name = 'hello'; console.log(name); console.log(globalName); } console.log(name); //->{ } 내부에서 정의된 변수는 외부에서 찾을 수 없음 console.log(globalName); //어디서든 가능 var (don't ever use this!) - var hoisting: (move decla..

Developer tool window: Ctrl +Shift + i mac: Ctrl +Option + i WEB API(Applicatin Programming Interface): 브라우저가 제공, 이해하는 함수 https://developer.mozilla.org/ko/docs/Web/API/Console_API Dev Tools_F12 console tab: 간단한 js 실행 sources tab: debugging(잘못된 부분 고치는것)시 유용 network tab: 발생, 데이터 검사 : JS 공식사이트 ecma-international.org -비추 Mozila.MDN 사이트 https://developer.mozilla.org/ - 추천 비공식 사이트 www.w3schools.com - ..