Modern TypeScript Progress Bar Library – BProgress

BProgress (the successor of NProgress) is a lightweight progress bar library that creates smooth animated loading indicators for web applications. The successor of npress

It generates a slim, animated progress bar at the top of the viewport, showing your users that something is happening in the background, like a page transition or a data fetch.

This can help manage user expectations during asynchronous operations and make the application feel more responsive.

Features:

• TypeScript implementation with clean, optimized syntax.
• CSS custom properties for easy styling without overriding classes.
• Configurable progress behavior with minimum/maximum values and animation easing.
• Multiple installation options, including CDN and package managers.
• Framework-agnostic core with dedicated framework packages (React, Next.js, Vue, and Remix).
• Indeterminate progress mode for unknown loading durations.
• Promise integration for automatic progress management.

Use Cases:

• Single Page Applications: Indicating route transitions and lazy-loaded component mounting in React, Vue, or Angular applications
• API-heavy dashboards: Providing visual feedback during data fetching operations, especially useful for analytics interfaces and admin panels
• Form submissions: Showing progress during multi-step forms or file upload processes where users need clear feedback
• Content management systems: Improving perceived performance during page loads and content updates in WordPress themes or custom CMS implementations

How to use it:

1. Install BProgress using your preferred package manager:

# Yarn
$ yarn add @bprogress/core

# NPM
$ npm install @bprogress/core

# PNPM
$ pnpm install @bprogress/core

# BUN
$ bun add @bprogress/core

2. Import the library and CSS styles in your JavaScript application:

import '@bprogress/core/css';
import { BProgress } from '@bprogress/core';

3. If you prefer not to use a package manager, you can link to the library directly from a CDN in your HTML.

<link rel="stylesheet" type="text/css" href="https://unpkg.com/@bprogress/core/dist/index.css" />
<script type="module">
  import { BProgress } from 'https://unpkg.com/@bprogress/core/dist/index.js';
  // Your code here
</script>

4. Start & complete the progress bar.

// Start the progress bar
BProgress.start();

// Complete the progress bar
BProgress.done();

5. Available options to customize the progress bar.

• minimum: The minimum percentage the bar can have.
• maximum: The maximum percentage the bar can have.
• template: The HTML string for the progress bar and spinner.
• easing: The CSS easing function for the animation.
• positionUsing: The CSS property used for positioning the bar: ‘translate3d’, ‘translate’, ‘margin’, ‘width’, ”.
• speed: The animation speed in milliseconds.
• trickle: Enables or disables the automatic incrementing animation.
• trickleSpeed: The speed of the trickle animation in milliseconds.
• showSpinner: Toggles the visibility of the loading spinner.
• barSelector: The CSS selector for the main progress bar element within the template.
• spinnerSelector: The CSS selector for the spinner element within the template.
• parent: The DOM element or selector where the progress bar is appended.
• direction: The direction of the progress bar animation ('ltr' or 'rtl').
• indeterminate: Puts the bar in an indeterminate (continuously animating) state.
• indeterminateSelector: The CSS selector for the indeterminate element within the template.

BProgress.configure({
 minimum: 0.08,
  maximum: 1,
  template: `<div class="bar"><div class="peg"></div></div>
   <div class="spinner"><div class="spinner-icon"></div></div>
   <div class="indeterminate"><div class="inc"></div><div class="dec"></div></div>`,
  easing: 'linear',
  positionUsing: 'width',
  speed: 200,
  trickle: true,
  trickleSpeed: 200,
  showSpinner: true,
  indeterminate: false,
  indeterminateSelector: '.indeterminate',
  barSelector: '.bar',
  spinnerSelector: '.spinner',
  parent: 'body',
  direction: 'ltr',
});

6. Full API Methods

• start(): Initializes and displays the progress bar
• done(force?: boolean): Completes and hides the progress bar, with optional force parameter
• set(percentage: number): Sets progress to specific value between 0 and 1
• inc(amount: number): Increments progress by specified amount
• dec(amount: number): Decrements progress by specified amount
• trickle(): Automatically increments progress by small amounts for perceived loading
• promise(promise: any): Integrates with Promise objects for automatic progress management
• pause(): Temporarily stops progress updates
• resume(): Resumes paused progress updates
• reset(): Resets progress bar to initial state
• isStarted(): Returns boolean indicating if progress bar is active
• isRendered(): Returns boolean indicating if progress bar element exists in DOM
• render(fromStart: boolean): Ensures progress bar element exists in DOM
• remove(element?: HTMLElement): Removes progress bar elements from DOM

7. Here’s a common usage pattern for a fetch request:

function fetchData() {
  BProgress.start();
  fetch('/api/data')
    .then(response => response.json())
    .then(data => {
      // process data
    })
    .catch(error => {
      console.error('Error fetching data:', error);
    })
    .finally(() => {
      BProgress.done();
    });
}

8. BProgress uses CSS custom properties for easy theming without JavaScript configuration:

:root {
  --bprogress-color: #ff6b35;                    /* Progress bar color */
  --bprogress-height: 3px;                       /* Bar thickness */
  --bprogress-spinner-size: 20px;                /* Spinner dimensions */
  --bprogress-spinner-animation-duration: 500ms; /* Spinner speed */
  --bprogress-spinner-border-size: 3px;          /* Spinner border width */
  --bprogress-box-shadow: 0 0 15px var(--bprogress-color); /* Glow effect */
  --bprogress-z-index: 99999;                    /* Stacking context */
  --bprogress-spinner-top: 20px;                 /* Spinner position */
  --bprogress-spinner-right: 20px;
}

FAQs:

Q: How do I prevent the progress bar from completing too quickly on fast connections?
A: Use the minimum configuration option to ensure the progress bar displays for a minimum duration, and consider implementing artificial delays with setTimeout before calling done(). We typically set a minimum 300ms display time for better user perception.

Q: Is it possible to have multiple progress bars on the same page?
A: BProgress follows a singleton pattern by design, but you can create multiple instances by using different parent containers and custom selectors. Configure each instance with unique barSelector, spinnerSelector, and parent options.

Q: How do I handle progress bars for file uploads with actual progress data?
A: Use the set() method with progress values from upload events. Monitor the XMLHttpRequest.upload.onprogress event and call BProgress.set(loaded / total) to reflect actual upload progress rather than using the automatic trickle functionality.

Related Reading:

• Google Like Slim Progress Bar Plugin – NProgress
• 10 Best JavaScript & CSS Progress Bar Components

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