Cannot get figlet to output text to commandline-CodePudding

When using figlet I am really struggling to output the text to the command line using the default example on https://www.npmjs.com/package/figlet.

I have a class and it has a method that once run should output some text to the command line.

My code looks like this:

/* eslint-disable no-console */
var figlet = require('figlet');

class Page {

  async run () {
    console.log('figlet start');
    console.log(figlet);
    //console.log(figlet.textSync('Hello World!', 'Standard'));
    figlet('Hello World!', 'Standard', function(err, data) {
      if (err) {
        console.log('Something went wrong...');
        console.dir(err);
        return;
      }
      console.log(data);
    });
    console.log('figlet end');
    process.exit(0);
  }
}

module.exports = {
  Page
};

The output from this is:

[Function: me] {
  text: [Function (anonymous)],
  textSync: [Function (anonymous)],
  metadata: [Function (anonymous)],
  defaults: [Function (anonymous)],
  parseFont: [Function (anonymous)],
  loadFont: [Function (anonymous)],
  loadFontSync: [Function (anonymous)],
  preloadFonts: [Function (anonymous)],
  figFonts: {},
  fonts: [Function (anonymous)],
  fontsSync: [Function (anonymous)]
}
figlet end

If I uncomment the line //console.log(figlet.textSync('Hello World!', 'Standard')); then is displays "Hello world!" twice.

I'm really scratching my head as to what it is I am doing wrong. I can run the examples in the figlet repo fine from my command line.

Perhaps I have fundamentally misunderstood something so it would be good to learn what that is.

CodePudding user response：

node.js is asynchronous, so process.exit(0); runs before figlet is finished, which shows in the output

if you comment out process.exit(0);, the last output should be figlet's "hello world"

so the output actually ends within figlet's callback, so you should move everything there:

/* eslint-disable no-console */
var figlet = require('figlet');

class Page {

  async run () {
    console.log('figlet start');
    console.log(figlet);
    //console.log(figlet.textSync('Hello World!', 'Standard'));
    figlet('Hello World!', 'Standard', function(err, data) {
      if (err) {
        console.log('Something went wrong...');
        console.dir(err);
        return;
      }
      console.log(data);
      console.log('figlet end');      
      process.exit(0);
    });
  }
}

module.exports = {
  Page
};