TIL150 Object.keys( ) function countNumberOfKeys(obj) { return Object.keys(obj).length; //return number of properties the given obj has using Object.keys( ) } function countNumberOfKeys(obj){ var count = 0; // if there are no keys, then it will automatically start at 0 and return count at 0 for (let key in obj){ count++; } return count; } 2020. 1. 8. push() function getAllLetters(str) { let arr = [ ]; // 빈 배열을 만든다. for(let i=0; i 2020. 1. 8. push() function getAllLetters(str) { let arr = [ ]; // 빈 배열을 만든다. for(let i=0; i 2020. 1. 8. prev 1 ··· 18 19 20 21 22 23 24 ··· 50 next