Learn POLYMER with Real Code Examples

Polymer enables developers to create custom HTML elements using the Web Components standard.

It provides syntactic sugar and utilities for templating, data binding, and component lifecycle.

Polymer encourages building applications with reusable, encapsulated components that work across frameworks.

Custom element creation via `Polymer()`

Property observers and computed properties

Shadow DOM encapsulation

Template-based declarative binding

Events, listeners, and lifecycle callbacks

Custom elements via `class MyElement extends PolymerElement`

Shadow DOM encapsulation

Property definitions and observers

Data binding (`[[value]]`, `{{value}}`)

Event handling in templates

src/ - components and source files

src/components/ - Web Components

src/styles/ - shared style modules

index.html - entry point

polymer.json - project configuration

Create a custom element class

Define template and styles

Register element with `customElements.define`

Use element in HTML pages

Build and deploy via Polymer CLI

Beginner: simple custom elements

Intermediate: reusable UI components

Advanced: SPAs using routing + Polymer CLI

Expert: cross-framework design systems

Community: contributing to Polymer Project and Lit ecosystem

More native than React/Vue - relies on browser standards

Less abstraction, more direct Web Components usage

Smaller ecosystem than React/Vue/Angular

Better for design systems than general SPAs

Polymer is predecessor to the modern LitElement

2013 – Polymer 0.x launched

2015 – Polymer 1.0 stable release

2017 – Polymer 2.0 with ES6 class-based APIs

2018 – Polymer 3.0 using ES Modules

2020–2025 – Shift toward LitElement ecosystem

Custom Element: user-defined HTML tag

Shadow DOM: isolated DOM tree

Template: HTML structure inside component

Observer: function that reacts to property changes

Property binding: linking DOM and JS values