SEECBC/FrontEnd/util/markdown/plugin/highlight.ts

import prism from 'prismjs'
import loadLanguages from 'prismjs/components/index'

function transformAlias(lang: string) {
  const map = {
    python3: 'python'
  } as { [key: string]: string }

  return map[lang] || lang
}

export default function highlight(str: string, lang: string) {
  if (lang) {
    const langCode = transformAlias(lang)
    if (!prism.languages[langCode]) {
      try {
        loadLanguages([langCode])
      } catch (e) {
        // eslint-disable-next-line no-console
        console.error(`lang ${langCode} is not supported by prism`)
      }
    }
    if (prism.languages[langCode]) {
      const code = prism.highlight(str, prism.languages[langCode], langCode)
      return `<pre class="language-${langCode}"><code>${code}</code></pre>`
    }
  }

  return `<pre class="language-text"><code>${str}</code></pre>` // use external default escaping
}