JS 005: Repeat and Spread Operator

by Nico D

JavaScript

var version = 1;
var exampleNumber = 1;
const log = function (message) {
  if (version < exampleNumber) {
    version = exampleNumber;
    document.write("<br/>");
  };
  const title = 'EXAMPLE ' + exampleNumber + ': ';
  document.write(title + message + "<br/>");
};
//////////////////////
exampleNumber = 1;
let count = 10,
    price = 0.25,
    message = `${count} items cost $${(count * price).toFixed(2)}.`;
log(message);
//////////////////////
exampleNumber = 2;
log("x".repeat(3));
log("hello".repeat(2));
log("abc".repeat(4));
//////////////////////
exampleNumber = 3;
const array1 = [1,2];
const array2 = [3,4];
const array3 = [...array1, ...array2];
const array3bis = [array1, array2];
log("Array 1 = " + JSON.stringify(array1));
log("Array 2 = " + JSON.stringify(array2));
log("Array 3 = " + JSON.stringify(array3));
log("Array 3bis = " + JSON.stringify(array3bis));
//////////////////////
exampleNumber = 4;
let values = [25, 50, 75, 100];
log(Math.max(...values));
log(Math.min(...values));
//////////////////////
exampleNumber = 5;
function pick(object, ...keys) {
    let result = Object.create(null);
    for (let i = 0; i < keys.length; i++) {
        result[keys[i]] = object[keys[i]];
    }
    return result;
}
let a = pick(values, 0, 2);
log(JSON.stringify(a, null, 1));