cls-demo.js

const cls = require('cls-hooked');
const ctx = cls.createNamespace('test-cls-context');

// result of this demo: 4 and 13
// despite ctx is "global", every async "context" has it's own strage and values are not mixed between timeouts

setTimeout(() => {
    ctx.run(() => {
        ctx.set('value', 1);
        setTimeout(() => {
            ctx.set('value', ctx.get('value') + 1);
            setTimeout(() => {
                ctx.set('value', ctx.get('value') + 2);
                process.nextTick(() => {
                    console.log(ctx.get('value'));
                })
            })
        })
    });
});

setTimeout(() => {
    ctx.run(() => {
        ctx.set('value', 10);
        setTimeout(() => {
            ctx.set('value', ctx.get('value') + 1);
            setTimeout(() => {
                ctx.set('value', ctx.get('value') + 2);
                process.nextTick(() => {
                    console.log(ctx.get('value'));
                })
            })
        })
    });
});