Differentiate runtime question about quickjs

[chqrlie]

You can test if an object is defined this way:

if (typeof window === 'undefined') {
    // not running in the browser
}

Is this what you were looking for?

I use this trick to detect if a script is being run by node vs: quickjs:

if (typeof require !== 'undefined') {
    // load the fs package in node.js
    var fs = require('fs');
}

// Use a precise clock if available
if (typeof performance !== "undefined") {
    // use more precise clock on NodeJS
    // need a method call on performance object
    get_clock = () => performance.now();
} else
if (typeof os !== "undefined") {
    // use more precise clock on QuickJS
    get_clock = os.now;
} else {
    // use Date.now and round up to the next millisecond
    get_clock = () => {
        var t0 = Date.now();
        var t;
        while ((t = Date.now()) == t0)
            continue;
        return t;
    }
}

[saghul]

In the friendly fork we have navigator.userAgent, since it's recommended by WinterCG.