리액트 문법

let a = 1;

const b = 2;

console.log(a);

function test(){

let a = 3;

  

  let sum = 0;

  for(let i=0; i<i; ++i){

  let b = 3;

    sum += i;

  }

  return sum;

}

let test1 = ()=>{

 let sum = 0;

  for(let i=0; i<i; ++i){

  let b = 3;

    sum += i;

  }

  return sum;

}

let test2 = ()=>{

 let sum = 0;

  for(let i=0; i<i; ++i){

  let b = 3;

    sum += i;

  }

  return `${sum}ddddd`;

}

const obj ={

x:1,

  y:2,

  u:3

}

let test3 = ()=>{

 let sum = 0;

  let {x,...testqq} = obj;

  for(let i=0; i<i; ++i){

  let b = 3;

    sum += i;

  }

  return {

  sum,i

  }

}

ReactDOM.render(<App />, document.getElementById('root'));

필요 출처 사이트

https://babeljs.io/repl#?babili=false&browsers=&build=&builtIns=false&spec=false&loose=false&code_lz=DYUwLgBAhhC8EEYDcAoAxgewHYGdICM4IAmVFdbHDUAOmAwHMAKKASjJQDMBXLNMAJbYIYEHiasA3igCQoSDHgBmVBAgo18iDm4BbIgAZVEThgBOTLQNhGIAgDwCkEANQuBUjRDngIhZcZqOvou8E5eAL5eZuDcZljaeqhRKFqieAhEErAAfNIQWsGGxqYWVjbODk6u7p5qPgREKl5Beq5hxlFqMWBxCcHJ5GliYMRZrLn5hW3wRl6llr7WtlXObh753lr-EM1qrSEdkdGx8RAABgAkksERACYPD-eDFLiQGPgAVnDSMgAeAC4EAAaLwATwBxFBam4AKUKBSwzwSnGkw0030s2MWkkf2BNAJ6TAAEdiREiB9PiVzItIMtKo41rVNg0_E1AolDnZOidemcWcFgQJjikAEogKD8AAiAHkALI0GJYO4gCz2ACCAAdNRAAPQ5YEQO4YNB6EBYMA0BjgACioF05rAACEwQBJO5MADkZgwGDAntY7HIwZDoZQQA&debug=false&forceAllTransforms=false&shippedProposals=false&circleciRepo=&evaluate=false&fileSize=false&timeTravel=false&sourceType=module&lineWrap=true&presets=es2015%2Creact%2Cstage-2&prettier=false&targets=&version=6.26.0&envVersion=