index.js

let { relative } = require('node:path')

function warningToString(warning) {
  let str = ''
  if (warning.node && warning.node.type !== 'root') {
    str +=
      warning.node.source.start.line +
      ':' +
      warning.node.source.start.column +
      '\t'
  }
  str += warning.text
  if (warning.plugin) {
    str += ' [' + warning.plugin + ']'
  }
  return str
}

const DEFAULT_STYLES = {
  'display': 'block',
  'z-index': '1000',

  /* not a problem for old browsers, box will still be on top of body */
  'position': 'fixed',
  'top': '0',
  'left': '0',
  'right': '0',

  'font-size': '.9em',
  'padding': '1.5em 1em 1.5em 4.5em' /* padding + background image padding */,

  /* background */
  'color': 'white',
  'background-color': '#DF4F5E',
  'background':
    'url("data:image/svg+xml;charset=utf-8,%3Csvg%20version%3D%221.1%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20xmlns%3Axlink%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxlink%22%20x%3D%220px%22%20y%3D%220px%22%20width%3D%2248px%22%20height%3D%2248px%22%20viewBox%3D%220%200%20512%20512%22%20enable-background%3D%22new%200%200%20512%20512%22%20xml%3Aspace%3D%22preserve%22%3E%3Cpath%20fill%3D%22%23A82734%22%20id%3D%22warning-4-icon%22%20d%3D%22M228.55%2C134.812h54.9v166.5h-54.9V134.812z%20M256%2C385.188c-16.362%2C0-29.626-13.264-29.626-29.625c0-16.362%2C13.264-29.627%2C29.626-29.627c16.361%2C0%2C29.625%2C13.265%2C29.625%2C29.627C285.625%2C371.924%2C272.361%2C385.188%2C256%2C385.188z%20M256%2C90c91.742%2C0%2C166%2C74.245%2C166%2C166c0%2C91.741-74.245%2C166-166%2C166c-91.742%2C0-166-74.245-166-166C90%2C164.259%2C164.245%2C90%2C256%2C90z%20M256%2C50C142.229%2C50%2C50%2C142.229%2C50%2C256s92.229%2C206%2C206%2C206s206-92.229%2C206-206S369.771%2C50%2C256%2C50z%22%2F%3E%3C%2Fsvg%3E") .5em no-repeat, #DF4F5E linear-gradient(#DF4F5E, #CE3741)',

  /* sugar */
  'border': '1px solid #C64F4B',
  'border-radius': '3px',
  'box-shadow': 'inset 0 1px 0 #EB8A93, 0 0 .3em rgba(0,0,0, .5)',

  /* nice font */
  'white-space': 'pre-wrap',
  'font-family': 'Menlo, Monaco, monospace',
  'text-shadow': '0 1px #A82734'
}

const plugin = (opts = {}) => {
  if (opts.disabled) {
    return function () {}
  }

  let styles = opts.styles ?? DEFAULT_STYLES

  return {
    OnceExit(root, { result }) {
      let warnings = result.warnings()
      if (warnings.length === 0) {
        return
      }

      let selector = 'html::before'
      if (opts?.selector) {
        selector = opts.selector
      } else {
        root.walkRules(rule => {
          if (
            rule.selector === 'html::before' ||
            rule.selector === 'html:before'
          ) {
            selector = 'html::after'
          }
        })
      }

      root.append({ selector })
      for (let style in styles) {
        root.last.append({ prop: style, value: styles[style] })
      }

      let content = warnings.map(message => {
        return warningToString(message).replace(/"/g, '\\"')
      })

      if (root.source.input.file) {
        content.unshift(
          relative(process.cwd(), root.source.input.file).replace(/\\/g, '/')
        )
      }

      content = content.join('\\00000a')

      root.last.append({ prop: 'content', value: `"${content}"` })
    },
    postcssPlugin: 'postcss-browser-reporter'
  }
}

plugin.postcss = true

module.exports = plugin