このエラーメッセージに関する原因と対処に関して説明します。
エラーメッセージ(英語)：
array add no duplicates
対処
関連リンク
how to prevent adding duplicate keys to a javascript array - Stack ...stackoverflow.com/.../how-to-prevent-adding-duplicate...
https://stackoverflow.com/questions/10757516/how-to-prevent-adding-duplicate-keys-to-a-javascript-ar・・・
Trying to prevent duplicate values to be added to an array ...stackoverflow.com/...prevent-duplicate...added...array/4...
https://stackoverflow.com/questions/46700862/trying-to-prevent-duplicate-values-to-be-added-to-an-ar・・・
How to Remove Array Duplicates in ES6 - DailyJS - Mediummedium.com/.../how-to-remove-array-duplicates-in-es6...
https://medium.com/dailyjs/how-to-remove-array-duplicates-in-es6-5daa8789641c