All files / src/helpers rgb.js

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// @flow
 
/**
 * Returns a string value for the color. The returned result is the smalles possible hex notation.
 *
 * @example
 * // Styles as object usage
 * const styles = {
 *   background: rgb('255, 205, 100'),
 *   background: rgb(255, 205, 100),
 *   background: rgb({ red: 255, green: 205, blue: 100 }),
 * }
 *
 * // styled-components usage
 * const div = styled.div`
 *   background: ${rgb('255, 205, 100')};
 *   background: ${rgb(255, 205, 100)};
 *   background: ${rgb({ red: 255, green: 205, blue: 100 })};
 * `
 *
 * // CSS in JS Output
 *
 * element {
 *   background: TODO
 * }
 */
 
type RgbColor = {
  red: number,
  green: number,
  blue: number,
}
 
function toHex(value) {
  const hex = value.toString(16)
  return hex.length === 1 ? `0${hex}` : hex
}
 
function rgb(value: RgbColor | number, green?: number, blue?: number): string {
  if (typeof value === 'number' && typeof green === 'number' && typeof blue === 'number') {
    return `#${toHex(value)}${toHex(green)}${toHex(blue)}`
  } else if (typeof value === 'object' && green === undefined && blue === undefined) {
    return `#${toHex(value.red)}${toHex(value.green)}${toHex(value.blue)}`
  }
 
  throw new Error('Passed invalid arguments to rgb, please pass multiple numbers e.g. rgb(255, 205, 100) or an object e.g. rgb({ red: 255, green: 205, blue: 100 }).')
}
 
export default rgb