How to Build Reusable Components in LWC

In modern Salesforce development, Lightning Web Components (LWC) have revolutionized the way developers create dynamic, efficient, and scalable user interfaces. One of the biggest advantages of using LWC is the ability to build reusable components — modules that can be used across multiple pages, apps, or projects with minimal code duplication.

This guide will help you understand how to build reusable components in LWC, why they’re important, and the best practices to follow in 2025 for scalable Salesforce development.

Understanding Reusability in LWC

Before diving into implementation, it’s important to understand what “reusable” means in the context of LWC. A reusable component is one that is:

• Modular – designed to perform one specific task or function.

• Configurable – accepts inputs (via @api properties) to change its behavior dynamically.

• Composable – can be easily integrated with other components.

• Independent – has minimal dependencies on the parent component.

Reusable LWCs help developers write clean, maintainable, and scalable code, ensuring faster development and consistent UI/UX across the Salesforce ecosystem.

Why Build Reusable Components in LWC?

1. Improved Efficiency

Once you create a reusable component, it can be used in multiple projects or modules without rewriting code.

2. Consistency Across the Platform

Reusable components ensure uniform styling and behavior across various Lightning pages.

3. Easier Maintenance

Updating one reusable component automatically reflects changes wherever it’s used.

4. Reduced Code Duplication

Reusability minimizes repetitive code, improving maintainability and performance.

5. Faster Development

By using a shared library of prebuilt LWCs, developers can quickly assemble applications instead of coding everything from scratch.

Core Principles of Reusable LWCs

1. Separation of Concerns

Each component should focus on a single responsibility. For example, a component that displays a list of records shouldn’t also handle data saving or filtering logic.

2. Parameterization Using @api

Expose properties using @api decorators to make components configurable by parent components.

3. Event Communication

Use custom events to communicate between child and parent components. This ensures components remain loosely coupled.

4. Composition Over Inheritance

Instead of duplicating code, create smaller components and compose them together to form more complex ones.

5. Encapsulation

Each LWC should manage its own styles, templates, and logic, protecting it from unintended external changes.

How to Build a Reusable Component in LWC

Let’s explore how to create and use a reusable Lightning Web Component with a practical example.

Step 1: Identify Common Functionality

Suppose multiple pages in your Salesforce app need a record search input box. Instead of rewriting the same code, create a reusable Search Component that can be used anywhere.

Step 2: Define the Component Structure

Create a new LWC folder named searchBox:

lwc/
 └── searchBox/
      ├── searchBox.html
      ├── searchBox.js
      ├── searchBox.js-meta.xml
      └── searchBox.css

Step 3: Create the Template (HTML)

Your component should have a dynamic search field:

<template>
    <lightning-input 
        type="search" 
        label={label} 
        placeholder={placeholder} 
        value={searchKey}
        onchange={handleChange}>
    </lightning-input>
</template>

Step 4: Define the Logic (JavaScript)

Make the component configurable and reusable:

import { LightningElement, api } from 'lwc';

export default class SearchBox extends LightningElement {
    @api label = 'Search';
    @api placeholder = 'Enter search text';
    searchKey = '';

    handleChange(event) {
        this.searchKey = event.target.value;
        const searchEvent = new CustomEvent('search', {
            detail: this.searchKey
        });
        this.dispatchEvent(searchEvent);
    }
}

This @api property allows you to customize the label and placeholder text, while the search event lets the parent component handle the search logic.

Step 5: Expose the Component

In the searchBox.js-meta.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
    <apiVersion>59.0</apiVersion>
    <isExposed>true</isExposed>
</LightningComponentBundle>

Step 6: Use the Reusable Component in Another LWC

Now, in your parent component (e.g., accountSearch), you can use the reusable search box:

<template>
    <c-search-box 
        label="Search Accounts" 
        placeholder="Type account name" 
        onsearch={handleSearch}>
    </c-search-box>
</template>

And handle the event in your parent’s JavaScript:

handleSearch(event) {
    const searchKey = event.detail;
    // Fetch results using Apex or filter existing list
}

You’ve just created a fully reusable search component that can be plugged into any page with customizable labels and event handling.

Advanced Techniques for Reusable LWCs

1. Dynamic Input Using Slots

Slots allow you to insert custom content into a reusable component. For example, create a modal component that displays any content passed by the parent.

<template>
    <section class="modal">
        <header>{title}</header>
        <slot></slot>
    </section>
</template>

This makes your component flexible enough to adapt to various content types without modification.

2. Use Composition for Complex UIs

Instead of building a massive single component, break it down into smaller parts like buttons, modals, and tables — then compose them together.

Example:

• dataTable component for rendering records.

• pagination component for navigating pages.

• filters component for search criteria.
  Combine them in a parent component to build a complete data management interface.

3. Reusable Utility Modules

You can also create utility JS files for common functions like validation, formatting, or API calls.

Example (utils.js):

const formatCurrency = (value) => `$${parseFloat(value).toFixed(2)}`;
export { formatCurrency };

Import it into multiple LWCs to maintain a consistent logic:

import { formatCurrency } from 'c/utils';

4. Using Custom Labels and Design Tokens

For multilingual and design-consistent components, use custom labels for text and design tokens for colors, spacing, and fonts.

5. Configurable CSS with Lightning Design System (SLDS)

Use SLDS utility classes to ensure your reusable components blend seamlessly with Salesforce’s UI style.

Best Practices for Building Reusable LWCs

1. Keep Components Simple and Focused

A reusable component should solve one problem well — not multiple.

2. Use @api Properties Wisely

Expose only necessary properties and avoid over-configuration to maintain clarity.

3. Implement Proper Documentation

Document each component’s purpose, inputs, and outputs for other developers to use easily.

4. Test Components Independently

Always test each LWC in isolation to ensure it behaves correctly before integrating it with others.

5. Maintain Version Control

When you update a reusable component, track changes properly in version control (Git) to avoid breaking dependencies.

6. Optimize for Performance

Avoid unnecessary re-renders and large data bindings. Use conditional rendering for efficiency.

7. Leverage Component Libraries

Maintain a shared component library within your Salesforce org or Git repository so developers can reuse and improve components collaboratively.

Real-World Use Cases for Reusable LWCs

• Reusable Toast Notifications – A single component to display success, warning, or error messages.

• Pagination Component – Used across various list views and data tables.

• Modal or Confirmation Dialog – Reused for different actions like delete, update, or approval.

• Custom Record Form – Dynamic form components that render fields based on metadata.

Common Mistakes to Avoid

• Overcomplicating the Component – Too many configurations can make a component difficult to maintain.

• Tight Coupling with Parent Logic – Avoid hardcoding dependencies.

• Ignoring Reusability from the Start – Plan for reusability during the design phase.

• Lack of Testing Across Use Cases – Ensure the component behaves correctly in different contexts.

Conclusion

Building reusable components in LWC is a smart development strategy that saves time, ensures consistency, and enhances maintainability across your Salesforce applications. By designing modular, configurable, and scalable LWCs, you create a foundation that can evolve with business needs.

As we move into 2025, Salesforce developers should focus on reusability, modular design, and performance optimization to deliver future-ready applications. Start small — identify repetitive UI patterns, turn them into components, and watch your development speed and quality improve dramatically.