javascript エラー「Uncaught TypeError: xxx.forEach is not a function」の解決方法

let obj = {
    "a": "1",
    "b": "2",
    "c": "3"
}

obj.forEach(function (v,i) {
    console.log(v);
});

Uncaught TypeError: obj.forEach is not a function

Uncaught TypeError: obj.forEach is not a function

TypeError: obj.forEach is not a function. (In 'obj.forEach(function (v,i) {
    console.log(v);
})', 'obj.forEach' is undefined)

let obj = {
    "a": "1",
    "b": "2",
    "c": "3"
}

console.log( Object.keys(obj) ) // ['a', 'b', 'c']

Object.keys(obj).forEach( function (v) {
    console.log(`key : ${v} value : ${obj[v]}`);
});

<ul class="foo">
    <li class="one">1</li>
    <li class="two">2</li>
    <li class="two">3</li>
</ul>

<button id="btn">削除</button>

<script>

'use strict';

document.getElementById('btn').addEventListener('click', function () {

    const elm = document.getElementsByClassName('two');

    if (0 < elm.length) {
        elm.forEach(function(v){ return v.remove() })
    }

});

</script>

document.getElementById('btn').addEventListener('click', function () {

    const elm = document.getElementsByClassName('two');

    if (0 < elm.length) {
        [...elm].forEach(function(v){ return v.remove() })
    }

});