Function handle

packages/tailwindcss/src/utilities.ts:2678–2681

(value)

  staticUtility(class="st">'bg-contain', [[class="st">'background-size', class="st">'contain']])
  functionalUtility(class="st">'bg-size', {
    handle(value) {
      if (!value) return
      return [decl(class="st">'background-size', value)]
    },
  })

  staticUtility(class="st">'bg-fixed', [[class="st">'background-attachment', class="st">'fixed']])