migrate-canvas-styled-to-tailwind

name	migrate-canvas-styled-to-tailwind
description	Migrate an apollo-react canvas component from Emotion styled-components to apollo-wind Tailwind classes following the BaseNode reference migration patterns

Migrate Canvas Styled Components to Tailwind

Overview

Migrate canvas components in packages/apollo-react/src/canvas/ from Emotion (@emotion/styled, @emotion/react) to Tailwind classes provided by apollo-wind. The goal is zero runtime CSS-in-JS: every component should use static Tailwind class strings (or CSS custom properties for dynamic dimensions), with cn() from apollo-wind used only where class-level overrides are needed (e.g. conditional border colors that must beat a base class).

When to Use

• Migrating any *.styles.ts file under packages/apollo-react/src/canvas/
• Component currently imports from @emotion/styled or @emotion/react
• Component uses styled.* or the css helper

Reference Files (live in repo)

These files are the canonical examples of the completed migration. Read them before starting:

• packages/apollo-react/src/canvas/components/BaseNode/BaseNodeContainer.tsx — Pattern C (conditional classes with cn())
• packages/apollo-react/src/canvas/components/BaseNode/BaseNodeInnerShape.tsx — Pattern A (inline static class string + CSS custom properties)
• packages/apollo-react/src/canvas/components/BaseNode/BaseNodeBadgeSlot.tsx — Pattern D (inline styles for positional offsets)
• packages/apollo-react/src/canvas/components/BaseNode/NodeLabel.tsx — Decomposed sub-components (Header, SubHeader, EditableLabel, EmptyLabelPlaceholder) using cx() for non-conflicting conditional classes
• packages/apollo-react/src/canvas/components/BaseNode/BaseNodeMissingManifest.tsx — Simple composition of the above primitives
• packages/apollo-react/src/canvas/components/BaseNode/BaseNode.tsx — Parent component: CSS custom property setup via useMemo, wiring to sub-components
• packages/apollo-react/src/canvas/constants.ts — Extracted magic numbers
• packages/apollo-wind/src/styles/tailwind.utilities.css — Custom Tailwind @keyframes and @utility definitions (see animate-glow)

Step-by-Step Process

Step 1: Audit the Styles File

Read the *.styles.ts file and catalog every styled component. For each one, identify:

• Static styles — CSS that never changes (borders, flex layout, font sizes)
• Prop-driven styles — CSS that varies by prop (shape, status, size)
• Dynamic numeric values — Pixel values computed from props (widths, heights, offsets)
• Animations / keyframes — Any @emotion/react keyframe usage

Create a migration plan showing which pattern (see Step 2) applies to each styled component. Get user approval before proceeding.

Step 2: Choose the Right Pattern for Each Styled Component

Pattern A: Static Tailwind Classes (preferred)

Use when all styles are known at build time. Inline the class string directly in the JSX — a string literal is the simplest and most readable form.

Before (Emotion):

const BaseIconWrapper = styled.div<{ shape?: string }>`
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--canvas-background-secondary);
  color: var(--canvas-foreground);
  border-radius: ${({ shape }) => shape === 'circle' ? '50%' : '8px'};
`;

After (Tailwind):

export const BaseInnerShape = memo(({ children }: Props) => (
  <div
    className="
      flex items-center justify-center overflow-hidden bg-surface text-foreground
      w-(--inner-size) h-(--inner-size) rounded-(--inner-radius)
      [&>svg]:w-(--icon-size) [&>svg]:h-(--icon-size)
    "
  >
    {children}
  </div>
));

Note: the shape-dependent border-radius moved to a CSS custom property (--inner-radius) computed by the parent. This lets the child's className be fully static.

Pattern B: CSS Custom Properties for Dynamic Dimensions

Use when numeric dimensions are computed from props (node width/height, scale factors). Set --custom-props via style on a single parent wrapper, then reference them with static Tailwind classes on children using w-(--varname) or [border-radius:var(--varname)] syntax.

Before (Emotion):

// Styled component with complex dimension calculations in template literal
const BaseContainer = styled.div<{ shape?: string; width?: number; height?: number }>`
  width: ${({ shape, width }) => {
    const defaultWidth = shape === 'rectangle' ? 288 : 96;
    return width ?? defaultWidth;
  }}px;
  height: ${({ height }) => height ?? 96}px;
  border-radius: ${({ shape }) => shape === 'circle' ? '50%' : '16px'};
`;

After (Tailwind + CSS vars):

// Parent computes vars once in useMemo
const nodeVars = useMemo((): React.CSSProperties => ({
  '--node-w': `${containerWidth}px`,
  '--node-h': numH ? `${numH}px` : 'auto',
  '--node-radius': shape === 'circle' ? '50%' : `${radius}px`,
} as React.CSSProperties), [containerWidth, numH, shape]);

// Wrapper applies vars; all children use static classes
<div style={nodeVars}>
  <div className="w-(--node-w) h-(--node-h) [border-radius:var(--node-radius)]">
    ...
  </div>
</div>

Key points:

• Compute CSS variable values in useMemo with relevant deps.
• Cast to React.CSSProperties (TS doesn't know about custom properties).
• Children's className strings are static — they never change, which is the perf win.

Pattern C: Conditional Classes with cn()

Use when Tailwind classes must override each other (e.g. border-brand must beat the base border-border). Import cn from @uipath/apollo-wind. Wrap in useMemo to avoid recomputation.

Before (Emotion):

const BaseContainer = styled.div<{ selected?: boolean; executionStatus?: string }>`
  border: 1.5px solid var(--canvas-border-de-emp);
  ${({ executionStatus }) => getExecutionStatusBorder(executionStatus)}
  ${({ selected }) => selected && css`
    border-color: var(--canvas-primary);
    outline: 4px solid var(--canvas-secondary-pressed);
  `}
`;

After (Tailwind + cn):

import { cn } from '@uipath/apollo-wind';

const className = useMemo(
  () => cn(
    'border-2 border-border bg-surface-overlay',           // base
    getStatusBorder(activeStatus),                          // override
    isSelected && 'border-brand',                           // override
    interactionState === 'disabled' && 'opacity-50 cursor-not-allowed',
  ),
  [activeStatus, isSelected, interactionState]
);

Use cn() only when you need class-level override semantics (conflicting utilities on the same CSS property). For classes that don't conflict, plain string concatenation or the local cx() utility from ../../utils/CssUtil is sufficient and faster.

Pattern D: Minimal Inline Styles for Truly Dynamic One-Off Values

Use for values that are both dynamic and don't warrant a CSS custom property (e.g. a single background color from a prop, or positional offsets from a constant).

Before (Emotion):

const BaseBadgeSlot = styled.div<{ position: string; shape?: string }>`
  position: absolute;
  width: 20px;
  height: 20px;
  ${({ position, shape }) => {
    const offset = shape === 'circle' ? '12px' : '6px';
    switch (position) {
      case 'top-left': return `top: ${offset}; left: ${offset};`;
      ...
    }
  }}
`;

After:

export const BaseBadgeSlot = memo(({ position, shape, children }: Props) => {
  const offset = shape === 'circle' ? NODE_BADGE_INSET_CIRCLE : NODE_BADGE_INSET_SQUARE;
  const style: React.CSSProperties = { width: NODE_BADGE_SIZE, height: NODE_BADGE_SIZE };
  switch (position) {
    case 'top-left': style.top = offset; style.left = offset; break;
    ...
  }
  return (
    <div className="absolute flex items-center justify-center bg-transparent" style={style}>
      {children}
    </div>
  );
});

Pass undefined (not {}) for style when there's no dynamic value, so React skips the style attribute entirely.

Step 3: Extract Magic Numbers to Constants

Move all pixel literals, grid multiples, and ratio calculations to packages/apollo-react/src/canvas/constants.ts. Name them descriptively and document the design reference.

Before (buried in styled component):

const GRID_UNIT = 16;
const NODE_HEIGHT_DEFAULT = GRID_UNIT * 6; // 96px

After (in constants.ts):

export const GRID_SPACING = 16;
export const NODE_HEIGHT_DEFAULT = GRID_SPACING * 6; // 96px
export const NODE_CONTAINER_RADIUS_RATIO = 32 / DEFAULT_NODE_SIZE; // ~0.333

Step 4: Decompose the Monolithic Styles File

Replace the single *.styles.ts with focused component files. Each new file should:

• Export one component (or a small cohesive group)
• Own its own interface for props
• Use memo where the component is a leaf / pure-render
• Live alongside the parent component (e.g. BaseNodeContainer.tsx next to BaseNode.tsx)

Naming convention: {ParentComponent}{Role}.tsx (e.g. BaseNodeContainer.tsx, BaseNodeInnerShape.tsx, BaseNodeBadgeSlot.tsx).

Step 5: Convert Styled Components One by One

For each styled component:

1. Create the replacement file with the appropriate pattern from Step 2.
2. Update imports in the parent component to use the new file instead of *.styles.ts.
3. Move prop logic out of CSS — conditional styles that were in template literals become:
   • Ternary expressions in className for simple cases
   • cn() calls for override semantics
   • Switch/map helper functions that return full literal class strings for multi-value mappings (see getStatusBorder() in BaseNodeContainer.tsx)
4. Remove emotion imports (css, styled, keyframes) from the parent.
5. Delete the styled component from the styles file once its replacement is wired in.

Step 6: Handle Animations and Keyframes

If the styles file uses @emotion/react keyframes:

1. Define the @keyframes rule in packages/apollo-wind/src/styles/tailwind.utilities.css.
2. Create a @utility that applies the animation (see animate-glow in that file).
3. Use the utility as a Tailwind class in the component.

Important: lightningcss bug. Avoid color-mix() or var() inside @keyframes blocks — lightningcss drops them silently. Instead, compute the mixed value in the @utility body using an internal --_private-var and reference that var in the keyframe:

@keyframes apollo-glow {
  0%   { box-shadow: 0 0 0 0 var(--_glow-shadow, currentColor); }
  70%  { box-shadow: 0 0 0 10px transparent; }
  100% { box-shadow: 0 0 0 0 transparent; }
}

@utility animate-glow {
  --_glow-shadow: color-mix(
    in srgb,
    var(--glow-color, currentColor) var(--glow-strength, 40%),
    transparent
  );
  will-change: box-shadow;
  animation: apollo-glow 2s infinite;
}

Consumers parameterize via [--glow-color:var(--error)] arbitrary value classes.

Step 7: Update Tests

• Mock cn from @uipath/apollo-wind in unit tests (simple concatenation is fine):

  vi.mock('@uipath/apollo-wind', () => ({
    cn: (...args: unknown[]) =>
      args.flat(Infinity).filter((v): v is string => typeof v === 'string' && v.length > 0).join(' '),
  }));
  

• Update any test assertions that relied on emotion-generated class names or inline style objects.
• Add data-testid and data-* attributes on containers for test queries (e.g. data-execution-status, data-interaction-state).

Step 8: Delete the Styles File

Once every styled component has been replaced and the parent no longer imports from *.styles.ts, delete the file.

Step 9: Verify

pnpm build
pnpm test
pnpm lint

Check Storybook visually for regressions if stories exist for the component.

Tailwind Class Reference (apollo-wind)

Common Mappings

Emotion pattern	Tailwind equivalent
display: flex	flex
align-items: center	items-center
justify-content: center	justify-center
position: relative	relative
position: absolute	absolute
cursor: pointer	cursor-pointer
border: 2px solid var(--canvas-border)	border-2 border-border
border-radius: 50%	rounded-full
border-radius: 16px	rounded-2xl
font-size: 13px	text-sm
font-size: 11px	text-xs
font-weight: 600	font-semibold
opacity: 0.5	opacity-50
overflow: hidden	overflow-hidden
white-space: nowrap; text-overflow: ellipsis	whitespace-nowrap text-ellipsis
-webkit-line-clamp: 3	line-clamp-3
word-break: break-word	wrap-break-word
Dynamic width via CSS var	w-(--varname)
Dynamic height via CSS var	h-(--varname)
Arbitrary CSS property via var	[border-radius:var(--varname)]
Child selector

Color Token Mappings

Emotion CSS variable	Tailwind class
var(--canvas-foreground)	text-foreground
var(--canvas-foreground-de-emp)	text-foreground-muted
var(--canvas-background)	bg-surface-overlay
var(--canvas-background-secondary)	bg-surface
var(--canvas-border-de-emp)	border-border
var(--canvas-primary)	border-brand
var(--canvas-error-icon)	border-error or text-error
var(--canvas-success-icon)	border-success
var(--canvas-warning-icon)	border-warning
var(--canvas-info)	border-info

Tailwind v4 Gotchas

• All class names must be literal strings. Tailwind v4 statically scans source files. Never interpolate class names: `border-${color}` won't work. Use a switch/map that returns full literal strings.
• color-mix() with var() inside @keyframes is dropped by lightningcss. Compute it outside the keyframe in a @utility body.
• field-sizing: content — use field-sizing-content (custom utility if needed).

Anti-Patterns to Avoid

Don't	Do instead
Keep @emotion/styled alongside Tailwind in the same component	Fully migrate the component; no hybrid state
Use cn() everywhere	Use cn() only when classes conflict/override; use static strings or cx() otherwise
Put useMemo around static class strings	Inline static strings directly in JSX
Create inline style objects on every render	Use CSS custom properties on a parent + static Tailwind classes on children
Add new *.styles.ts files	Colocate styles as Tailwind classes in the component file
Use Tailwind @apply in CSS files	Use Tailwind classes directly in JSX

Checklist

Before marking migration complete:

• *.styles.ts file deleted
• No @emotion/styled or @emotion/react imports remain in the component tree
• All magic numbers moved to constants.ts
• New sub-components use memo where appropriate
• Tests updated and passing
• Storybook stories render correctly (visual check)
• Build passes (pnpm build)
• Lint passes (pnpm lint)