Lightning Web Components (LWC) @api and @track decorators make component rendering a breeze, but they can be tricky to debug. The reason they can be tricky is because they are implemented using ES6 Proxies. Proxies allow LWC to transparently know what properties are being rendered in your template but they are tricky to inspect in the Chrome Dev Tools. The best approach to debugging @api and @track properties is to enable the custom dev formatter that comes out of the box with LWC.

Inspecting with Dev Formatter DisabledPermalink

For example, let’s say we have a simple component that contains a single @track property:

import { LightningElement, track } from 'lwc';

export default class App extends LightningElement {
    @track property = { value: 'Hello World' }
}

When we inspect property, Chrome will include all kinds of information about the proxy that is used to implement @track:

Inspecting tracked property without dev tools formatter

Inspecting with Dev Formatter EnabledPermalink

After we enable the custom dev formatter, our debugging experience becomes much better:

Inspecting tracked property with dev tools formatter

Enabling Custom Dev FormatterPermalink

Enabling the custom dev formatter is easy:

1) Open the Web Inspector
2) Open the Web Inspector Settings 		Open Web Inspector Settings
3) Scroll down to "Console" section and check "Enable Custom Formatters" Scroll down to 'Console' section and check 'Enable Custom Formatters'

Happy Coding!