sgds-components（SGDS 组件）

SGDS Components Setup Skill

Prerequisites and framework integration for using <sgds-*> web components.

Installation

npm install @govtechsg/sgds-web-component
# or
pnpm add @govtechsg/sgds-web-component

Import the library once at your app entry point:

import "@govtechsg/sgds-web-component";

Framework Integration

React

React version determines which import to use.

React 19+ (client-side, e.g. Vite)

React 19 supports native custom elements directly — import once at the app entry point, then use the web component tag anywhere:

import "@govtechsg/sgds-web-component";

function App() {
  return (
    <sgds-button variant="primary" onsgds-blur={(e) => console.log(e)}>
      Click Me
    </sgds-button>
  );
}

Custom event syntax in React 19: prefix the event name with on in lowercase (sgds-blur → onsgds-blur).

Using Next.js? Next.js is SSR-based and requires a different setup — see the Next.js section below.

Complex props (arrays, objects) can be passed declaratively:

import "@govtechsg/sgds-web-component";

const steps = [
  { component: <Step1 />, stepHeader: "Personal details" },
  { component: <Step2 />, stepHeader: "Contact details" },
];

function App() {
  return <sgds-stepper steps={steps}></sgds-stepper>;
}

React 18 and below

React ≤18 does not support custom element events or complex props natively. Use the React wrapper components:

import { SgdsButton } from "@govtechsg/sgds-web-component/react";

function App() {
  return (
    <SgdsButton variant="primary" onSgdsBlur={(e) => console.log(e)}>
      Click Me
    </SgdsButton>
  );
}

React wrapper event naming: sgds-blur → onSgdsBlur, sgds-change → onSgdsChange (prefix on, camelCase applies to every hyphen-separated word).

Accessing component methods in React ≤18 (via useRef):

import { useRef } from "react";
import type { SgdsStepper as SStep } from "@govtechsg/sgds-web-component/components";
import SgdsStepper from "@govtechsg/sgds-web-component/react/stepper/index.js";

function StepperComponent() {
  const stepperRef = useRef<SStep>(null);
  return <SgdsStepper steps={steps} ref={stepperRef} />;
}

Note: The React wrappers will be phased out in a future major version. Migrate to React 19+ native usage when possible.

Official docs: https://webcomponent.designsystem.tech.gov.sg/?path=/docs/frameworks-react--docs

Next.js

Next.js is an SSR framework — web components rely on browser APIs and will error if imported at the module level during server-side rendering.

Step 1 — Create sgds.tsx (library loader)

'use client';

import { useEffect } from 'react';

const SgdsLibraryLoader = () => {
  useEffect(() => {
    (async () => {
      await import('@govtechsg/sgds-web-component');
    })();
  }, []);

  return null;
};

export default SgdsLibraryLoader;

Step 2 — Add to root layout <head>

// src/app/layout.tsx
import SgdsLibraryLoader from './sgds';

export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    <html lang="en">
      <head>
        <SgdsLibraryLoader />
      </head>
      <body>
        {children}
      </body>
    </html>
  );
}

Step 3 — Use components directly with suppressHydrationWarning

<sgds-masthead suppressHydrationWarning></sgds-masthead>

Step 4 — TypeScript support — add a types.d.ts at the project root and reference the SGDS React type definitions. This gives full IntelliSense for props and typed CustomEvent detail payloads on all sgds-* elements:

Use an ES import in any .d.ts file included by your tsconfig:

import "@govtechsg/sgds-web-component/types/react";

Events in Next.js — due to hydration timing, wire custom events via useEffect + addEventListener rather than declarative React props:

'use client';
import { useEffect, useRef } from 'react';

export default function MyInput() {
  const ref = useRef<any>(null);

  useEffect(() => {
    const el = ref.current;
    if (!el) return;
    const handler = (e: Event) => console.log((e.target as any).value);
    el.addEventListener('sgds-input', handler);
    return () => el.removeEventListener('sgds-input', handler);
  }, []);

  return <sgds-input ref={ref} suppressHydrationWarning />;
}

Organise into reusable React components — do not inline useEffect / addEventListener alongside business logic. Wrap each SGDS element in a dedicated client component that exposes typed props and forwards events via callbacks:

// components/sgds/SgdsInput.tsx
'use client';
import { useEffect, useRef, useCallback } from 'react';

interface SgdsInputProps {
  label?: string;
  placeholder?: string;
  value?: string;
  onSgdsInput?: (value: string) => void;
  onSgdsChange?: (value: string) => void;
}

export default function SgdsInput({ label, placeholder, value, onSgdsInput, onSgdsChange }: SgdsInputProps) {
  const ref = useRef<any>(null);
  const onSgdsInputRef = useRef(onSgdsInput);
  const onSgdsChangeRef = useRef(onSgdsChange);
  onSgdsInputRef.current = onSgdsInput;
  onSgdsChangeRef.current = onSgdsChange;

  useEffect(() => {
    const el = ref.current;
    if (!el) return;

    const handleInput = (e: Event) => onSgdsInputRef.current?.((e.target as any).value);
    const handleChange = (e: Event) => onSgdsChangeRef.current?.((e.target as any).value);

    el.addEventListener('sgds-input', handleInput);
    el.addEventListener('sgds-change', handleChange);
    return () => {
      el.removeEventListener('sgds-input', handleInput);
      el.removeEventListener('sgds-change', handleChange);
    };
  }, []);

  return (
    <sgds-input
      ref={ref}
      label={label}
      placeholder={placeholder}
      value={value}
      suppressHydrationWarning
    />
  );
}

Then consume it like any React component — no event wiring in the page:

// app/contact/page.tsx
'use client';
import SgdsInput from '@/components/sgds/SgdsInput';

export default function ContactPage() {
  const [name, setName] = useState('');
  return <SgdsInput label="Name" placeholder="Enter name" onSgdsInput={setName} />;
}

Place all SGDS wrappers under a shared directory (e.g. components/sgds/) so they are discoverable and reusable across pages.

See the official Next.js integration docs for more detail.

Vue

Vue 3 supports web components natively — no SGDS-specific wrappers exist. Refer to the Vue + web components documentation for configuration. The SGDS-specific filter for suppressing unknown element warnings is tag.startsWith("sgds-").

Angular

Angular supports web components natively via CUSTOM_ELEMENTS_SCHEMA — no SGDS-specific wrappers exist. Refer to the Angular elements documentation for configuration.

Troubleshooting Component Behaviour

When a component behaves unexpectedly — wrong event fired, property not reflected, slot not rendering — read the compiled source directly. It contains full method bodies, event logic, internal defaults, and edge-case handling that no documentation captures.

Read from node_modules/@govtechsg/sgds-web-component — this directory is present once the package is installed:

node_modules/@govtechsg/sgds-web-component/components/Accordion/sgds-accordion.js
node_modules/@govtechsg/sgds-web-component/components/Accordion/sgds-accordion-item.js
node_modules/@govtechsg/sgds-web-component/components/Accordion/sgds-accordion.d.ts

Replace Accordion/sgds-accordion with the relevant component folder and file name. The .js file contains the full implementation; the .d.ts file lists all properties, types, events, slots, and JSDoc descriptions.

If node_modules is absent — the package has not been installed. Ask the user to run their normal install step (npm install / pnpm install) before inspecting source files.

For AI agents: The primary decision tree is React version + rendering mode:

• React 19+ CSR (Vite etc.): native <sgds-*> tag + direct import, event props lowercase with on prefix (onsgds-change)
• Next.js (SSR): SgdsLibraryLoader + useEffect dynamic import — never a top-level import; wire events via addEventListener in useEffect
• React ≤18: SGDS React wrapper package, camelCase event props (onSgdsChange)
• Vue / Angular: standard web component integration; SGDS-specific detail for Vue is tag.startsWith("sgds-") to suppress unknown element warnings

When a user reports unexpected component behaviour (wrong event, property not reflecting, slot not rendering), direct them to read the compiled source before trying anything else — see the Troubleshooting Component Behaviour section above.

Global rule — never set explicit widths on SGDS components. Do not add width, style="width:...", or fixed-width utility classes (e.g. sgds:w-40) directly on any <sgds-*> element. Width is controlled by the parent layout — use flex, grid, or wrapper divs to constrain it. The only exception is when a user explicitly requests a fixed width.

Available Components

Form Input Components

When building forms, use these 9 form input components to capture user data:

1. <sgds-input> — text fields
2. <sgds-textarea> — multi-line text
3. <sgds-select> — dropdown selection
4. <sgds-checkbox> / <sgds-checkbox-group> — multiple choice
5. <sgds-radio> / <sgds-radio-group> — single choice
6. <sgds-combo-box> — searchable select
7. <sgds-datepicker> — date input
8. <sgds-file-upload> — file picker
9. <sgds-quantity-toggle> — numeric counter

DO NOT use in forms (these are feedback/state, not input):

• <sgds-switch> — This is a feedback component (displays toggle state), not a form input. Use <sgds-checkbox> or <sgds-radio-group> to collect user choice instead.
• Other non-input components (Alert, Badge, Button, Card, etc.) — These are layout/feedback, not form controls.

For form layout patterns (field pairing, spacing, width constraints, multi-step forms with <sgds-stepper>, header hierarchy), see the sgds-blocks form layout skill. | Feedback | Alert | → reference/alert.md | | Feedback | Spinner | → reference/spinner.md | | Feedback | Skeleton | → reference/skeleton.md | | Feedback | Progress Bar | → reference/progress-bar.md | | Feedback | Toast | → reference/toast.md | | Feedback | System Banner | → reference/system-banner.md |