node.js - Javascript script file code behaves differently then command in node -

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i have created script (block 1) , fails import anythign array. if take code , execute line line (block 2) in command line node works fine

block 1:

var fs = require('fs'); var readline = require('readline'); var filename = process.argv[2];//filename var content = []; console.log(filename); readline.createinterface({     input: fs.createreadstream(filename),     terminal: false }).on('line', function (line) {    content.push(line); }); console.log(content.length); 

block 2: (each line entered sequentially)

fs = require('fs');  readline = require('readline');  filename = "filename.txt";  content = [];  readline.createinterface({     input: fs.createreadstream(filename),     terminal: false }).on('line', function (line) {    content.push(line); });  content; 

the console.log(filename) in block 1 prints out correct name, console.log(content.length) prints "0", in node repl content has upwards of 1700 entries.

i using node v6.9.4 in linux environment, , executing both blocks on same computer. missing obvious here?

thanks

you can expected output when use close event

readline.createinterface({     input: fs.createreadstream(filename),     terminal: false }).on('line', function (line) {    content.push(line); }).on('close', function(){   console.log(content.length); }) 

when enter in node shell, file input stream completes in interval take type in next line, , hence content.length available. when executed in browser memory, engine reaches line before input has completed being read interface.