refactor: hook context

Author: wan2land

default_hooks.ts

@@ -1,4 +1,4 @@
-import type { Hook, PrimitiveType } from "./types.ts";
+import type { Hook, HookContext, PrimitiveType } from "./types.ts";
 import { printArgs } from "./utils.ts";
 
 const VALID_MALE_VALUES = new Set<PrimitiveType>([
@@ -16,19 +16,21 @@ const VALID_FEMALE_VALUES = new Set<PrimitiveType>([
   "Female",
 ]);
 
+const contextMatchedMap = new WeakMap<HookContext, string>();
+
 function createGenderHook(gender: "male" | "female"): Hook {
-  return (source, args, ctx) => {
-    if (ctx.metadata.matched) {
-      return ctx.out;
+  return (ctx, args) => {
+    if (contextMatchedMap.has(ctx)) {
+      return contextMatchedMap.get(ctx)!;
     }
     if (
-      gender === "male" && VALID_MALE_VALUES.has(source) ||
-      gender === "female" && VALID_FEMALE_VALUES.has(source)
+      gender === "male" && VALID_MALE_VALUES.has(ctx.original) ||
+      gender === "female" && VALID_FEMALE_VALUES.has(ctx.original)
     ) {
-      ctx.metadata.matched = true;
-      return printArgs(args);
+      const result = printArgs(args);
+      contextMatchedMap.set(ctx, result);
+      return result;
     }
-    return "";
   };
 }
 
@@ -40,28 +42,27 @@ function getPluralRules(locale: string) {
   return pluralRules.get(locale)!;
 }
 
-const symPluralRule = Symbol("pluralRule");
+const contextPluralMap = new WeakMap<HookContext, Intl.LDMLPluralRule>();
 
 function createPluralHook(pluralRule: Intl.LDMLPluralRule): Hook {
-  return (source, args, ctx, info) => {
-    if (ctx.metadata.matched) {
-      return ctx.out;
+  return (ctx, args) => {
+    if (contextMatchedMap.has(ctx)) {
+      return contextMatchedMap.get(ctx)!;
     }
-    let selectedPluralRule = ctx.metadata[symPluralRule] as
-      | Intl.LDMLPluralRule
-      | undefined;
-    if (!ctx.metadata[symPluralRule]) {
-      selectedPluralRule = ctx.metadata[symPluralRule] = getPluralRules(
-        info.locale ?? "en",
-      ).select(+(source ?? 0));
+    let selectedPluralRule = contextPluralMap.get(ctx);
+    if (!selectedPluralRule) {
+      selectedPluralRule = getPluralRules(ctx.locale ?? "en").select(
+        +(ctx.original ?? 0),
+      );
+      contextPluralMap.set(ctx, selectedPluralRule);
     }
     if (
       selectedPluralRule === pluralRule
     ) {
-      ctx.metadata.matched = true;
-      return printArgs(args);
+      const result = printArgs(args);
+      contextMatchedMap.set(ctx, result);
+      return result;
     }
-    return "";
   };
 }
 
@@ -79,9 +80,9 @@ export const defaultHooks: Record<string, Hook> = {
   other: createPluralHook("other"),
 
   // else
-  else: (_, args, ctx) => {
-    if (ctx.metadata.matched) {
-      return ctx.out;
+  else: (ctx, args) => {
+    if (contextMatchedMap.has(ctx)) {
+      return contextMatchedMap.get(ctx)!;
     }
     return printArgs(args);
   },

interpreter.test.ts

@@ -33,8 +33,8 @@ Deno.test("interpreter, basic template value", () => {
 Deno.test("interpreter, template value with method", () => {
   const runtime = new Interpreter({
     hooks: {
-      upper: (source, _, ctx) => `${ctx.out ?? source}`.toUpperCase(),
-      trim: (source, _, ctx) => `${ctx.out ?? source}`.trim(),
+      upper: (ctx) => `${ctx.current}`.toUpperCase(),
+      trim: (ctx) => `${ctx.current}`.trim(),
     },
   });
 

interpreter.ts

@@ -5,7 +5,6 @@ import type {
   Hook,
   HookArg,
   HookContext,
-  HookInfo,
   PrimitiveType,
   Runtime,
   TaggedTemplateHandler,
@@ -107,15 +106,19 @@ function getSafeMethod(
   return null;
 }
 
-function createDecorator(hooks: Record<string, Hook>, info: HookInfo) {
-  return (source: PrimitiveType) => {
+function createDecorator(
+  hooks: Record<string, Hook>,
+  baseCtx: Omit<HookContext, "original" | "current">,
+) {
+  return (value: PrimitiveType) => {
     const ctx: HookContext = {
-      out: null,
-      metadata: {},
+      original: value,
+      current: value,
+      ...baseCtx,
     };
     const decoratedSource = new Proxy({
       toString() {
-        return ctx.out ?? `${source}`;
+        return `${ctx.current ?? ""}`;
       },
     }, {
       get(target, prop) {
@@ -125,8 +128,7 @@ function createDecorator(hooks: Record<string, Hook>, info: HookInfo) {
         if (prop in hooks) {
           const hook = hooks[prop as string];
           return (...args: HookArg[]) => {
-            const nextOut = hook(source, args, ctx, info);
-            ctx.out = nextOut;
+            ctx.current = hook(ctx, args);
             return decoratedSource;
           };
         }

mod.ts

@@ -3,7 +3,6 @@ export type {
   Hook,
   HookArg,
   HookContext,
-  HookInfo,
   PrimitiveType,
   Runtime,
 } from "./types.ts";

types.ts

@@ -11,20 +11,12 @@ export interface Runtime {
 }
 
 export interface HookContext {
-  out: string | null;
-  metadata: Record<string | symbol, unknown>;
-}
-
-export interface HookInfo {
+  original: PrimitiveType;
+  current: PrimitiveType;
   locale: string | null;
 }
 
-export type Hook = (
-  source: PrimitiveType,
-  args: HookArg[],
-  ctx: HookContext,
-  info: HookInfo,
-) => string | null;
+export type Hook = (ctx: HookContext, args: HookArg[]) => PrimitiveType;
 
 export type TaggedTemplateHandler = (
   strings: TemplateStringsArray,