Interpreter

Pausing and Resuming the Terminal

When using commands that do something asynchronous you should pause the terminal and resume it when you're done. This is needed when for example you want to execute a sequence of command or when you don't want the user to execute a command when one is already running. When you don't pause, you may get race conditions and unexpected behavior.

const url = 'https://jsonplaceholder.typicode.com/posts/1';
const term = $('body').terminal({
    test() {
        this.pause();
        fetch(url).then(res => {
            return res.json();
        }).then(data => {
            this.echo(data.title);
            this.resume();
        });
    }
});

pause/resume is an old API. You can also use modern API, when you return a promise from the command.

const url = 'https://jsonplaceholder.typicode.com/posts/1';
const term = $('body').terminal({
    test() {
        return fetch(url).then(res => {
            return res.json();
        }).then(data => {
            this.echo(data.title);
        });
    }
});

And because async/await is a syntax sugare of returing a promise from a function you can use it as well.

const url = 'https://jsonplaceholder.typicode.com/posts/1';
const term = $('body').terminal({
    async test() {
        const res = await fetch(url);
        const data = await res.json();
        this.echo(data.title);
    }
});

The return value from the intepreter is also printed on the terminal, so you can use:

const url = 'https://jsonplaceholder.typicode.com/posts/1';
const term = $('body').terminal({
    async test() {
        const res = await fetch(url);
        const data = await res.json();
        return data.title;
    }
});