Allow plugins and presets to have explicit names.

packages/babel-core/src/config/option-assertions.js

@@ -146,16 +146,31 @@ function assertPluginItem(
     if (value.length === 0) {
       throw new Error(`.${key}[${index}] must include an object`);
     }
-    if (value.length > 2) {
-      throw new Error(`.${key}[${index}] may only be a two-tuple`);
+
+    if (value.length > 3) {
+      throw new Error(
+        `.${key}[${index}] may only be a two-tuple or three-tuple`,
+      );
     }
 
     assertPluginTarget(key, index, true, value[0]);
 
-    if (value.length === 2) {
+    if (value.length > 1) {
       const opts = value[1];
-      if (opts != null && (typeof opts !== "object" || Array.isArray(opts))) {
-        throw new Error(`.${key}[${index}][1] must be an object, or undefined`);
+      if (
+        opts !== undefined &&
+        opts !== false &&
+        (typeof opts !== "object" || Array.isArray(opts))
+      ) {
+        throw new Error(
+          `.${key}[${index}][1] must be an object, false, or undefined`,
+        );
+      }
+    }
+    if (value.length === 3) {
+      const name = value[2];
+      if (name !== undefined && typeof name !== "string") {
+        throw new Error(`.${key}[${index}][2] must be a string, or undefined`);
       }
     }
   } else {

packages/babel-core/src/config/option-manager.js

@@ -141,6 +141,7 @@ class OptionManager {
 }
 
 type BasicDescriptor = {
+  name: string | void,
   value: {} | Function,
   options: {} | void,
   dirname: string,
@@ -262,6 +263,7 @@ const instantiatePlugin = makeWeakCache(
 
     if (plugin.inherits) {
       const inheritsDescriptor = {
+        name: undefined,
         alias: `${alias}$inherits`,
         value: plugin.inherits,
         options,
@@ -327,11 +329,17 @@ function createDescriptor(
     ownPass?: boolean,
   },
 ): BasicDescriptor {
+  let name;
   let options;
   let value = pair;
   if (Array.isArray(value)) {
+    if (value.length === 3) {
+      // $FlowIgnore - Flow doesn't like the multiple tuple types.
+      [value, options, name] = value;
+    } else {
       [value, options] = value;
     }
+  }
 
   let filepath = null;
   if (typeof value === "string") {
@@ -366,6 +374,7 @@ function createDescriptor(
   }
 
   return {
+    name,
     alias: filepath || `${alias}$${index}`,
     value,
     options,

packages/babel-core/src/config/options.js

@@ -187,8 +187,13 @@ export type EnvSet<T> = {
 export type IgnoreItem = string | Function | RegExp;
 export type IgnoreList = $ReadOnlyArray<IgnoreItem>;
 
+export type PluginOptions = {} | void;
 export type PluginTarget = string | {} | Function;
-export type PluginItem = PluginTarget | [PluginTarget, {} | void];
+export type PluginItem =
+  | Plugin
+  | PluginTarget
+  | [PluginTarget, PluginOptions]
+  | [PluginTarget, PluginOptions, string];
 export type PluginList = $ReadOnlyArray<PluginItem>;
 
 export type SourceMapsOption = boolean | "inline" | "both";