ES2022のArray.prototype.atは今の所遅い (2021/10/16時点) - Qiita

Array.prototype.myat = function (n) { // ToInteger() abstract op n = Math.trunc(n) || 0; // Allow negative indexing from the end if (n < 0) n += this.length; // OOB access is guaranteed to return undefined if (n < 0 || n >= this.length) return undefined; // Otherwise, this is just normal property access return this[n]; } // myat 昇順 { const startTime = (new Date()).getTime(); for (let n = 0; n < 10