javascript - intergrate function readline from node.js module into read_line function to get user input -

//normal nodejs module readline  const readline = require('readline');  //i want integrate readline module function read_line can user input use read_line ,but mind  wrong.  //i know reason js function not blocked function,but not familiar nodejs,how can block subsequent code run?  function read_line() {      var input;      const rl = readline.createinterface({          input: process.stdin,          output: process.stdout      });      rl.on('line', function (input) {          this.input = input;          rl.close();      });      return input;  }    //it run right now,return undefined  var s = read_line();  //i want console user input  console.log(s);

i want integrate readline module function read_line can user input use read_line ,i　need help!

readline asynchronous function

rl.on('line', function (input) {     this.input = input;     rl.close(); }); 

the function wait 'line' event triggered

when call function read_line() run synchronous , return input;

you can use callback function, when 'line' event triggered callback function called value

const readline = require('readline');  function read_line(cb) {     const rl = readline.createinterface({         input: process.stdin,         output: process.stdout     });     rl.on('line', function (input) {         cb(input)         rl.close();     }); }  read_line(function(input){     console.log(input); });