Vue, Angular &amp; Svelte

Angular's input() Function: Passing Data to Components

Angular's input() function lets a parent pass data to a child, defining the child's public API. Use it to configure a component, like passing a value to a slider. The footgun: the returned signal is read-only; the child cannot modify its own input.

Svelte Props: Passing Data with `export let`

In Svelte, export let turns a variable into a prop, letting a parent component pass data down. It's how you pass a userName to a ProfileCard component. The footgun: forgetting export creates a private variable, not a prop, so data isn't received.

Vue Custom Events: Child-to-Parent Communication

Think of $emit as a child component sending a flare up to its parent. It's how children report actions upwards, reversing the top-down flow of props. Use it to trigger parent state changes, like closing a modal. The footgun: events don't bubble.

Angular @Output(): Child Components Reporting Up

An @Output() lets a child component tell its parent something happened, using an EventEmitter. It’s the standard way to handle events like button clicks that the parent needs to act on. The footgun is forgetting to actually .emit() the event.

intermediate1 min read

Handling Basic DOM Events in Svelte

Svelte handles DOM events with on:eventname syntax in your markup, linking elements to functions in your script. This is for user interactions within a component, not for parent-child communication. The footgun is confusing this with custom component events.

Vue Slots: Projecting Content into Components

Think of a Vue slot as a picture frame: the child component defines the frame, and the parent provides the picture. This is used for reusable layouts or buttons where the structure is fixed but the content is dynamic.

Angular Content Projection with ng-content

ng-content creates a "slot" in a component's template, letting you project parent content into it. Use this for reusable wrappers like cards or dialogs. The key footgun: never use @if on ng-content, as the content is always rendered, even if hidden.

Vue Provide/Inject: Skip Prop Drilling

Vue's provide/inject lets an ancestor component share data directly with any descendant, avoiding the tedious 'prop drilling' chain. Use it for app-wide data like user info or theme settings. The footgun: providing a simple value is not reactive by default.

Svelte Context API: Avoid Prop-Drilling

Svelte's Context API lets a parent component provide data to any descendant, avoiding 'prop-drilling'. It's ideal for sharing app-wide state like user info or themes. The key footgun: calling getContext without a parent setContext will throw an error.

Svelte Slot Props: Child Informs, Parent Renders

Svelte slot props let a child component pass data up to its parent's slot. This is key for reusable list components where the child provides data for each item, but the parent controls the rendering. The footgun: the let: directive goes on the component tag.

Angular View Encapsulation: Walling Off Your Component Styles

View Encapsulation walls off a component's CSS to prevent styles from leaking in or out. By default, Angular emulates a Shadow DOM to scope styles, but you can change this. The footgun is using None to fix a style, creating global CSS conflicts.

Angular: Dynamic Component Loading

Programmatically create and render components anywhere in your app, not just where you've hardcoded them. Use it for dynamic dashboards or modal dialogs. The footgun is forgetting to manually destroy components, which leads to memory leaks.

Vue's v-if vs. v-show: When to Use Which

v-if adds or removes elements from the DOM; v-show just hides them with CSS. Use v-if for conditions that rarely change (like admin access) and v-show for frequent toggles (like a dropdown menu), as it has a lower toggle cost.

Angular Structural Directives: Shape Your DOM

Structural directives shape your DOM by adding, removing, or manipulating HTML elements. Use *ngIf to show/hide a block or *ngFor to loop over a list. The footgun is forgetting the asterisk (*), which is critical syntactic sugar for a more complex template.

Vue's v-model: Two-Way Binding Made Simple

v-model creates a two-way binding that synchronizes form inputs with your JavaScript data. Use it on any form element like an input or textarea. The footgun: it ignores initial HTML attributes; your JavaScript state is always the single source of truth.

Angular Two-Way Binding: [(ngModel)]

Think of [(ngModel)] as a walkie-talkie for data, syncing a component property with a template view. It's used in forms where user input immediately updates a variable, and vice-versa. The footgun is overusing it, which creates tangled data flows.

Vue List Rendering: Why `key` is Not Optional

Think of key as a license plate for each item in a list. Without it, Vue just repaints items in order. With key, Vue tracks and preserves each item's state across re-renders. This is vital for dynamic lists with stateful components, like form inputs.

*ngFor trackBy: Smarter DOM Updates in Angular

*ngFor's trackBy tells Angular how to uniquely identify items in a list. This prevents it from destroying and recreating the entire list in the DOM on every data update, instead allowing it to reuse existing elements.

Vue Template Refs: Reaching Past the Virtual DOM

Vue template refs give you a direct handle to a DOM element, bypassing the declarative model. This is for tasks like programmatically focusing an input or initializing a 3rd-party library. The main footgun: the ref is null until the component has mounted.