wip: better experimental feature warnings

packages/compiler-sfc/src/warn.ts

@@ -1,12 +1,27 @@
 const hasWarned: Record<string, boolean> = {}
 
 export function warnOnce(msg: string) {
-  if (!hasWarned[msg]) {
+  const isNodeProd =
+    typeof process !== 'undefined' && process.env.NODE_ENV === 'production'
+  if (!isNodeProd && !__TEST__ && !hasWarned[msg]) {
     hasWarned[msg] = true
     warn(msg)
   }
 }
 
 export function warn(msg: string) {
-  console.warn(`\x1b[33m[@vue/compiler-sfc] ${msg}\x1b[0m\n`)
+  console.warn(
+    `\x1b[1m\x1b[33m[@vue/compiler-sfc]\x1b[0m\x1b[33m ${msg}\x1b[0m\n`
+  )
+}
+
+export function warnExperimental(feature: string, rfcId: number) {
+  warnOnce(
+    `${feature} is still an experimental proposal.\n` +
+      `Follow its status at https://github.com/vuejs/rfcs/pull/${rfcId}.`
+  )
+  warnOnce(
+    `When using experimental features,\n` +
+      `it is recommended to pin your vue dependencies to exact versions to avoid breakage.`
+  )
 }