typescript-styled-components-px2rem


TypeScript transformer for convert px to rem units of styled-components

1. Use postcss-plugin-px2rem to process all css text in template strings.

2. Add a runtime px2rem function polyfill to process expression embedded in template strings when enable transformRuntime option.

Babel plugin with similar functionality：babel-plugin-styled-components-px2rem.

Table of Contents

- Requirement
- Usage
* ttypescript
* rollup
* webpack
* Jest
- Composition
- Options
- Transform Runtime
* FunctionExpression
* ArrowFunctionExpression
* PropertyAccessExpression
* ConditionalExpression
* Other Expressions

Requirement

You need to install the following peerDependencies of typescript-styled-components-px2rem into your project at the same time:

``json
{
"peerDependencies": {
"typescript": "^3.0.0",
"postcss": "^7.0.0"
}
}
`

Usage

$3

see example

The use of React and styled-components test cases.

$3

Integration with rollup-plugin-typescript2 and ttypescript：

`js
import typescript2 from 'rollup-plugin-typescript2';
import tts from 'ttypescript';

export default {
// ... other rollup configs
plugins: [
// ...other rollup plugins
typescript2({
typescript: tts,
objectHashIgnoreUnknownHack: true,
tsconfigOverride: {
compilerOptions: {
module: 'ES2015',
plugins: [
{
transform: 'typescript-styled-components-px2rem',
rootValue: 100,
unitPrecision: 5,
minPixelValue: 0,
multiplier: 1,
tags: ['styled', 'css', 'createGlobalStyle', 'keyframes'],
transformRuntime: false,
},
],
},
},
}),
// ...other rollup plugins
],
};
`

$3

Integration with awesome-typescript-loader or ts-loader：

`js
const createCustomTransformer = require('typescript-styled-components-px2rem').default;

const customTransformer = createCustomTransformer({
rootValue: 100,
unitPrecision: 5,
minPixelValue: 0,
multiplier: 1,
tags: ['styled', 'css', 'createGlobalStyle', 'keyframes'],
transformRuntime: false,
});

module.exports = {
// ... other webpack configs
module: {
rules: [
{
test: /\.tsx?$/,
// loader: 'awesome-typescript-loader',
loader: 'ts-loader', // ts-loader or awesome-typescript-loader
options: {
// ... other loader options
getCustomTransformers: () => ({ before: [customTransformer] }),
},
},
],
},
};
`

$3

Integration with ts-jest and ttypescript:

jest.config.js:

`js
module.exports = {
// other jest configs
globals: {
'ts-jest': {
compiler: 'ttypescript',
},
},
};
`

tsconfig.json:

`json
{
"compilerOptions": {
"plugins": [
{
"transform": "typescript-styled-components-px2rem",
"type": "config",
"rootValue": 100,
"unitPrecision": 5,
"minPixelValue": 0,
"multiplier": 1,
"tags": ["styled", "css", "createGlobalStyle", "keyframes"],
"transformRuntime": false
}
]
}
}
`

Composition

It should be put before typescript-plugin-styled-components

tsconfig.json:

`json
{
"compilerOptions": {
"plugins": [
{
"transform": "typescript-styled-components-px2rem",
"type": "config"
},
{
"transform": "typescript-plugin-styled-components",
"type": "config"
}
]
}
}
`

Options

| name | type | required | default | description |
| :-- | :-: | :-: | :-- | --: |
| rootValue | number | false | 100 | The root element font size |
| unitPrecision | number | false | 5 | The decimal numbers to allow the REM units to grow to |
| minPixelValue | number | false | 0 | Set the minimum pixel value to replace |
| multiplier | number | false | 1 | The multiplier of input value |
| tags | string[] | false | ["styled", "css", "createGlobalStyle", "keyframes"] | styled-components template literal tagged |
| transformRuntime | boolean | false | false | since 1.1.0，enable transformation of all expressions that embedded in template strings |

Simple version of the formula：

`js
const input = '32px'; // the value in css text
const pixels = parseFloat(input);

if (pixels < minPixelValue) {
return input;
}

const fixedVal = toFixed((pixels * multiplier) / rootValue, unitPrecision);

return ${fixedVal}rem;
`

Remaining options are consistent with postcss-plugin-px2rem.

Transform Runtime

If enabled transformRuntime option, all supported expressions embedded in template strings are processed as follows:

Note: Only expression that end with px will be processed.

$3

source code:

`typescript
import styled from 'styled-components';

export const FunctionExpression = styled.button<{ width?: number | string }>
width: ${function(props) {
return props.width;
}}px; / Block Body /
${props => (props.disabled ? 'height: 400px' : 'height: 200px')};
;
`

compiled:

`javascript
import styled from 'styled-components';

export const FunctionExpression = styled.button
width: ${(...args) =>
px2rem_1(function(props) {
return props.width;
}, ...args)}; / Block Body /
${props => (props.disabled ? 'height: 4rem' : 'height: 2rem')};
;

function px2rem_1(input, ...args) {
if (typeof input === 'function') return px2rem_1(input(...args), ...args);
var value = parseFloat(input);
var pixels = Number.isNaN(value) ? 0 : value;
if (Math.abs(pixels) < 0) return ${pixels}px;
var multiplier = Math.pow(10, 5 + 1);
var wholeNumber = Math.floor(((pixels 1) / 100) multiplier);
return ${(Math.round(wholeNumber / 10) * 10) / multiplier}rem;
}
`

$3

source code:

`typescript
import styled from 'styled-components';

const height = '44';
export const ArrowFunction = styled.input.attrs(props => ({
type: 'password',
size: props.size || '16px',
width: props.width || 100,
}))
color: palevioletred;
font-size: 14px;
border: 1px solid palevioletred;
border-radius: 8px;
width: ${props => props.width}px; / PropertyAccess Body /
height: ${() => height}px; / Identifier Body /
line-height: ${() => '44'}px; / StringLiteral Body /
margin: ${() => 32}px; / NumericLiteral Body /
padding: ${props => props.size};
;
export const ArrowFunctionWithBlockBody = styled.button<{ width?: number | string }>
width: ${props => {
if (props.width) {
return props.width;
} else {
return 0;
}
}}px; / Block Body /
${props => (props.disabled ? 'height: 400px' : 'height: 200px')};
;
export const ArrowFunctionWithBinaryBody = styled.button<{ height?: number }>
${props =>
props.disabled &&

width: 200px;
font-size: 14px;
};
height: ${props => !props.disabled && props.height}px; / Binary Body /
;
export const ArrowFunctionWithConditionalBody = styled.button<{ height?: number }>
height: ${props => (props.height ? height : 100)}px; / Conditional Body /
;
`

compiled:

`javascript
import styled from 'styled-components';
const height = '44';
export const ArrowFunction = styled.input.attrs(props => ({
type: 'password',
size: props.size || '0.16rem',
width: props.width || 100,
}))
color: palevioletred;
font-size: 0.14rem;
border: 1px solid palevioletred;
border-radius: 0.08rem;
width: ${props => px2rem_1(props.width)}; / PropertyAccess Body /
height: ${() => px2rem_1(height)}; / Identifier Body /
line-height: ${() => px2rem_1('44')}; / StringLiteral Body /
margin: ${() => px2rem_1(32)}; / NumericLiteral Body /
padding: ${props => props.size};
;
export const ArrowFunctionWithBlockBody = styled.button
width: ${props =>
px2rem_1(() => {
if (props.width) {
return props.width;
} else {
return 0;
}
})}; / Block Body /
${props => (props.disabled ? 'height: 4rem' : 'height: 2rem')};
;
export const ArrowFunctionWithBinaryBody = styled.button
${props =>
props.disabled &&

width: 2rem;
font-size: 0.14rem;
};
height: ${props => px2rem_1(!props.disabled && props.height)}; / Binary Body /
;
export const ArrowFunctionWithConditionalBody = styled.button
height: ${props => (props.height ? px2rem_1(height) : px2rem_1(100))}; / Conditional Body /
;
function px2rem_1(input, ...args) {
if (typeof input === 'function') return px2rem_1(input(...args), ...args);
var value = parseFloat(input);
var pixels = Number.isNaN(value) ? 0 : value;
if (Math.abs(pixels) < 0) return ${pixels}px;
var multiplier = Math.pow(10, 5 + 1);
var wholeNumber = Math.floor(((pixels 1) / 100) multiplier);
return ${(Math.round(wholeNumber / 10) * 10) / multiplier}rem;
}
`

$3

source code:

`typescript
import styled from 'styled-components';

export const PropertyAccessExpression = styled.button<{ width: number; height: string }>(
props =>
width: ${props.width}px;
height: ${props.height}; / Note: Only expression end with 'px' will be processed. /
,
);
`

compiled:

`javascript
import styled from 'styled-components';
export const PropertyAccessExpression = styled.button(
props =>
width: ${px2rem_1(props.width)};
height: ${props.height}; / Note: Only expression end with 'px' will be processed. /
,
);
function px2rem_1(input, ...args) {
if (typeof input === 'function') return px2rem_1(input(...args), ...args);
var value = parseFloat(input);
var pixels = Number.isNaN(value) ? 0 : value;
if (Math.abs(pixels) < 0) return ${pixels}px;
var multiplier = Math.pow(10, 5 + 1);
var wholeNumber = Math.floor(((pixels 1) / 100) multiplier);
return ${(Math.round(wholeNumber / 10) * 10) / multiplier}rem;
}
`

$3

source code:

`typescript jsx
import React from 'react';
import styled from 'styled-components';

export const ConditionalExpression = function({ fontSize }: { fontSize?: unknown }) {
const StyledButton = styled.button
font-size: ${typeof fontSize === 'number' ? fontSize : props => props?.theme.fontSize}px;
;

return ;
};
export const ConditionalExpressionWhenTrue = function({ fontSize }: { fontSize?: unknown }) {
const StyledButton = styled.button
font-size: ${typeof fontSize !== 'number' ? props => props?.theme.fontSize : fontSize}px;
;

return ;
};
`

compiled:

`javascript
import React from 'react';
import styled from 'styled-components';
export const ConditionalExpression = function({ fontSize }) {
const StyledButton = styled.button
font-size: ${typeof fontSize === 'number' ? px2rem_1(fontSize) : props => px2rem_1(props?.theme.fontSize)};
;
return React.createElement(StyledButton, null);
};
export const ConditionalExpressionWhenTrue = function({ fontSize }) {
const StyledButton = styled.button
font-size: ${typeof fontSize !== 'number' ? props => px2rem_1(props?.theme.fontSize) : px2rem_1(fontSize)};
;
return React.createElement(StyledButton, null);
};
function px2rem_1(input, ...args) {
if (typeof input === 'function') return px2rem_1(input(...args), ...args);
var value = parseFloat(input);
var pixels = Number.isNaN(value) ? 0 : value;
if (Math.abs(pixels) < 0) return ${pixels}px;
var multiplier = Math.pow(10, 5 + 1);
var wholeNumber = Math.floor(((pixels 1) / 100) multiplier);
return ${(Math.round(wholeNumber / 10) * 10) / multiplier}rem;
}
`

$3

Identifier, CallExpression, BinaryExpression, ...

source code:

`typescript
import styled, { css, createGlobalStyle } from 'styled-components';

const fontSize = 18;
export const GlobalStyle = createGlobalStyle
html body {
font-size: ${fontSize}px;
}
;

function getHeight() {
const height = 100;

return height / 2;
}
const mixins = css
padding: 0 16px;
;
export const MixinsButton = styled.button
${mixins};
height: ${getHeight()}px;
;

const condition = false;
function calc() {
return 20;
}
export const BinaryExpression = styled.button
${condition ||

width: 200px;
};
height: ${condition || 100}px;
padding: ${40 + 50}px 8px ${4}px 16px;
line-height: ${calc() - 2}px;
;
`

compiled:

`javascript
import styled, { css, createGlobalStyle } from 'styled-components';
const fontSize = 18;
export const GlobalStyle = createGlobalStyle
html body {
font-size: ${px2rem_1(fontSize)};
}
;
function getHeight() {
const height = 100;
return height / 2;
}
const mixins = css
padding: 0 0.16rem;
;
export const MixinsButton = styled.button
${mixins};
height: ${px2rem_1(getHeight())};
;
const condition = false;
function calc() {
return 20;
}
export const BinaryExpression = styled.button
${condition ||

width: 2rem;
};
height: ${px2rem_1(condition || 100)};
padding: ${px2rem_1(40 + 50)} 0.08rem ${px2rem_1(4)} 0.16rem;
line-height: ${px2rem_1(calc() - 2)};
;

function px2rem_1(input, ...args) {
if (typeof input === 'function') return px2rem_1(input(...args), ...args);
var value = parseFloat(input);
var pixels = Number.isNaN(value) ? 0 : value;
if (Math.abs(pixels) < 0) return ${pixels}px;
var multiplier = Math.pow(10, 5 + 1);
var wholeNumber = Math.floor(((pixels 1) / 100) multiplier);
return ${(Math.round(wholeNumber / 10) * 10) / multiplier}rem;
}
``