题解 | #找出字符串中第一个只出现一次的字符#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    // Write your code here
    while(line = await readline()){
        let tokens = line.split('');
        let arr = [];
        for(let i = 0; i< tokens.length; i++) {
            let oriInx = tokens.indexOf(tokens[i]);
            if(oriInx == i) {
                arr.push(tokens[i]);
            } else {
                let inx = arr.indexOf(tokens[i]);
                arr.splice(inx, 1);
            }
        }
        console.log(arr[0] || -1);
    }
}()