在node.js中执行命令后杀死进程

Question

I would like to kill process (or exit them) after my commands will complete. I have this code, but process exits immediately.

var gplay = require('google-play-scraper');

gplay.list({
    category: gplay.category.GAME_ACTION,
    collection: gplay.collection.TOP_FREE,
    start: 0,
    num: 120
  })
  .then(console.log, console.log);

gplay.list({
    category: gplay.category.GAME_ACTION,
    collection: gplay.collection.TOP_FREE,
    start: 120,
    num: 120
  })
  .then(console.log, console.log);
process.exit();

I run this by node script.js > output.txt , because i want to write output to file. I don't know other method.

Answer 1

Javascript is highly asynchronous in nature that means after invoking the first function call it will immediately move to the next statement. In your case there are two possible ways:

1. Either put the next line of execution inside the then() of the first one and put exit() inside the then() block of second call.
2. Use async https://caolan.github.io/async/
3. Or simply remove exit();

Answer 2

You can use Promise.all

It returns a single Promise that resolves when all of the promises in the iterable argument have resolved or when the iterable argument contains no promises. It rejects with the reason of the first promise that rejects.

The callback displayThenExit will display the results then exits the node process

var gplay = require('google-play-scraper');

var p1 = gplay.list({
    category: gplay.category.GAME_ACTION,
    collection: gplay.collection.TOP_FREE,
    start: 0,
    num: 2
  })  

var p2 = gplay.list({
    category: gplay.category.GAME_ACTION,
    collection: gplay.collection.TOP_FREE,
    start: 2,
    num: 2
  })  
var displayThenExit = function(result){
    console.log(result);
    process.exit(0);
}

Promise.all([p1, p2]).then(displayThenExit, console.log);

ps: I set num: 2 to limit the number of entries returned for testing purpose