obetame

const age = 2;
function example(str) {
    eval(str);
    console.log(age);
}

example('const age=3;');             //output：2
example("'use strict'; var age=6;"); //output：2
example('var age=4;');               // output: 4

obetame

const obj = {
    a: 1,
    b: 2,
    c: 3,
};

with (obj) {
    d = 4;
}
console.log(obj) // output: {a: 1, b: 2, c: 3}

obetame

const obj = {
    a: 1,
    b: 2,
    c: 3,
};

with (obj) {
    a = 3;
    b = 4;
    c = 5;

obetame

function Person(name, age) {
    this.name = name;
    this.age = age;
    
    this.getName = function() {
        return this.name;
    }
}
Person.prototype.getAge = function() {
    return this.age;

obetame

var age = 2;
const person = {
    age: 1,
    doSomething(name) {
        console.log(this === person);
        console.log(this.age);
        console.log(name);
    },
};
const extractFn = person.doSomething;

obetame

var age = 2;
const person = {
    age: 1,
    doSomething() {
        console.log(this === person); // output: true
        console.log(this.age); // output: 1
    },
};
person.doSomething();

obetame

function str2ab(str) {
  const buf = new ArrayBuffer(str.length*2); // 2 bytes for each char
  const bufView = new Uint16Array(buf);
  for (let i=0, strLen=str.length; i < strLen; i++) {
    bufView[i] = str.charCodeAt(i);
  }
  return buf;
}
function ab2str(buf) {
  return String.fromCharCode.apply(null, new Uint8Array(buf));

obetame

html, body {
  height: 100%;
  margin: 0;
}

.app {
  height: 100%;
  display: grid;
  grid-template-rows: 45px 1fr;
  grid-template-columns: 200px 1fr;