@primer/react/lib/hooks/useResponsiveValue.js

An implementation of GitHub's Primer Design System using React

'use strict';

var useMedia = require('./useMedia.js');

// This file contains utilities for working with responsive values.

// The viewport range values from @primer/primtives don't work in Chrome
// because they use `em` units inside `calc()` (e.g., calc(48em - 0.02px)).
// As a temporary workaround, we're hardcoding the viewport ranges in `px` units.
// TODO: Use viewport range tokens from @primer/primitives
const viewportRanges = {
  narrow: '(max-width: calc(768px - 0.02px))',
  // < 768px
  regular: '(min-width: 768px)',
  // >= 768px
  wide: '(min-width: 1400px)' // >= 1400px
};

/**
 * Checks if the value is a responsive value.
 * In other words, is it an object with viewport range keys?
 */
// eslint-disable-next-line @typescript-eslint/no-explicit-any
function isResponsiveValue(value) {
  return typeof value === 'object' && Object.keys(value).some(key => ['narrow', 'regular', 'wide'].includes(key));
}

/**
 * Resolves responsive values based on the current viewport width.
 * For example, if the current viewport width is narrow (less than 768px), the value of `{regular: 'foo', narrow: 'bar'}` will resolve to `'bar'`.
 *
 * @example
 * const value = useResponsiveValue({regular: 'foo', narrow: 'bar'})
 * console.log(value) // 'bar'
 */
// TODO: Improve SSR support
function useResponsiveValue(value, fallback) {
  // Check viewport size
  // TODO: What is the performance cost of creating media query listeners in this hook?
  const isNarrowViewport = useMedia.useMedia(viewportRanges.narrow, false);
  const isRegularViewport = useMedia.useMedia(viewportRanges.regular, false);
  const isWideViewport = useMedia.useMedia(viewportRanges.wide, false);
  if (isResponsiveValue(value)) {
    // If we've reached this line, we know that value is a responsive value
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    const responsiveValue = value;
    if (isNarrowViewport && 'narrow' in responsiveValue) {
      return responsiveValue.narrow;
    } else if (isWideViewport && 'wide' in responsiveValue) {
      return responsiveValue.wide;
    } else if (isRegularViewport && 'regular' in responsiveValue) {
      return responsiveValue.regular;
    } else {
      return fallback;
    }
  } else {
    // If we've reached this line, we know that value is not a responsive value
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    return value;
  }
}

exports.isResponsiveValue = isResponsiveValue;
exports.useResponsiveValue = useResponsiveValue;
exports.viewportRanges = viewportRanges;