If statement 如何使用javascript比较/过滤2个数组中的值，并将唯一值推送到数组末尾

我有这段代码，我试图通过循环两个数组并使用IF条件来比较数组。我觉得我的循环和IF语句不正确。无论如何，我想要的是将

RED

的值从

newWords

推送到

oldWords

数组中，这样

oldWords

就等于

['TEST'，'EAR'，'RED]

。我希望保持这种顺序，因为基本上每次输入新值时，我都希望将它们附加到我的

oldWords

数组的末尾

let oldWords = ['TEST', 'EAR'];
let newWords = ['TEST', 'RED', 'EAR'];

function compareArr() {

    for (const oldWord of oldWords) {
        for (const newWord of newWords) {
            if (newWord !== oldWord) {
                oldWords.push(newWord)
            } 
        }
    }
}

compareArr();

// I would like to insert the word RED from newWords to the array of oldWords.
// I want the output of oldWords to be ['TEST', 'EAR', 'RED'] , it is important that RED is at the end.