单行输入输出

const readline = require("readline");
const rl = readline.createInterface({ 
    input: process.stdin,
    output:process.stdout,
});

rl.on("line",function(line){
    //直接在这里输出，只能用console.log，不能用return
    console.log(line)
})

多行输入输出

const readline = require("readline");
const rl = readline.createInterface({ 
    input: process.stdin,
    output:process.stdout,
});

let lineArr = []
rl.on("line",function(line){
    lineArr.push(line.toLowerCase())
}).on("close",function(){
    //可以在这里输出，也可以像单行输入一样在上面输出，看具体情况
    console.log(fun(lineArr))
})

function fun(){
    let inputStr = lineArr[0]
    let str = lineArr[1]
    let count = 0
    for(let i=0;i<lineArr[0].length;i++){
        if(lineArr[0][i] != str){
            continue
        }else{
            count++
        }
    }
    return count
}