PostCSS Viewport Height Fix

PostCSS plugin to solve the popular problem when 100vh doesn’t fit the mobile browser screen.

Inspiration

The viewport height which we use as "vh" unit in css does not give the actual viewport height but gives the height of the browser window. This plugin is an implememtation of CSS Tricks article on this issue.

Installation

yarn add postcss-vh-fix
# --- or ----
npm install --save postcss-vh-fix

And then add this javascript to public/index.html.

;(function () {
  var viewportVariable = 'vh'
  function setViewportProperty(doc) {
    var prevClientHeight
    var variable = '--' + (viewportVariable || 'vh')
    function handleResize() {
      var clientHeight = doc.clientHeight
      if (clientHeight === prevClientHeight) return
      requestAnimationFrame(function updateViewportHeight() {
        doc.style.setProperty(variable, clientHeight * 0.01 + 'px')
        prevClientHeight = clientHeight
      })
    }
    handleResize()
    return handleResize
  }
  window.addEventListener('resize', setViewportProperty(document.documentElement))
})()

Check you project for existed PostCSS config: postcss.config.js in the project root, "postcss" section in package.json or postcss in bundle config.

If you already use PostCSS, add the plugin to plugins list:

module.exports = {
  plugins: [
+   require('postcss-vh-fix'),
    require('autoprefixer')
  ]
}

If you use it in Nuxt：

export default defineNuxtConfig({
	postcss: {
	  plugins: {
	    'tailwindcss': {},
+      'postcss-vh-fix': {},
		},
	},
})

If you do not use PostCSS, add it according to official docs and set this plugin in settings.

Configuration

You really will rarely need this. Use this when you have some conflicting css variable. We use --vh as variable to fix the viewport height. You can use --vh or any other variable of your choice.

Configure postcss to use your variable.

export default defineNuxtConfig({
	postcss: {
	  plugins: {
	    'tailwindcss': {},
+      'postcss-vh-fix': {
+          variable: 'xxvh'
+       },
		},
	},
})

Example Output

.container {
  /* Input example */
  height: 100vh;
  min-height: 50vh;
  max-height: 75vh;
  margin: -1vh;
}

.container {
  /* Output example */
  height: 100vh;
  height: calc(var(--vh, 1vh) * 100);
  min-height: calc(var(--vh, 1vh) * 50);
  max-height: calc(var(--vh, 1vh) * 75);
  margin: calc(var(--vh, 1vh) * -1);
}