Fix Result deep toObject when a parent is an Array (#4681).

Author: ricmoo

src.ts/abi/coders/abstract-coder.ts

@@ -3,6 +3,7 @@ import {
     defineProperties, concat, getBytesCopy, getNumber, hexlify,
     toBeArray, toBigInt, toNumber,
     assert, assertArgument
+    /*, isError*/
 } from "../../utils/index.js";
 
 import type { BigNumberish, BytesLike } from "../../utils/index.js";
@@ -19,12 +20,44 @@ const passProperties = [ "then" ];
 
 const _guard = { };
 
+const resultNames: WeakMap<Result, ReadonlyArray<null | string>> = new WeakMap();
+
+function getNames(result: Result): ReadonlyArray<null | string> {
+    return resultNames.get(result)!;
+}
+function setNames(result: Result, names: ReadonlyArray<null | string>): void {
+    resultNames.set(result, names);
+}
+
 function throwError(name: string, error: Error): never {
     const wrapped = new Error(`deferred error during ABI decoding triggered accessing ${ name }`);
     (<any>wrapped).error = error;
     throw wrapped;
 }
 
+function toObject(names: ReadonlyArray<null | string>, items: Result, deep?: boolean): Record<string, any> | Array<any> {
+    if (names.indexOf(null) >= 0) {
+        return items.map((item, index) => {
+            if (item instanceof Result) {
+                return toObject(getNames(item), item, deep);
+            }
+            return item;
+        });
+    }
+
+    return (<Array<string>>names).reduce((accum, name, index) => {
+        let item = items.getValue(name);
+        if (!(name in accum)) {
+            if (deep && item instanceof Result) {
+                item = toObject(getNames(item), item, deep);
+            }
+            accum[name] = item;
+        }
+        return accum;
+    }, <Record<string, any>>{ });
+}
+
+
 /**
  *  A [[Result]] is a sub-class of Array, which allows accessing any
  *  of its values either positionally by its index or, if keys are
@@ -33,6 +66,9 @@ function throwError(name: string, error: Error): never {
  *  @_docloc: api/abi
  */
 export class Result extends Array<any> {
+    // No longer used; but cannot be removed as it will remove the
+    // #private field from the .d.ts which may break backwards
+    // compatibility
     readonly #names: ReadonlyArray<null | string>;
 
     [ K: string | number ]: any
@@ -73,21 +109,25 @@ export class Result extends Array<any> {
         }, <Map<string, number>>(new Map()));
 
         // Remove any key thats not unique
-        this.#names = Object.freeze(items.map((item, index) => {
+        setNames(this, Object.freeze(items.map((item, index) => {
             const name = names[index];
             if (name != null && nameCounts.get(name) === 1) {
                 return name;
             }
             return null;
-        }));
+        })));
+
+        // Dummy operations to prevent TypeScript from complaining
+        this.#names = [ ];
+        if (this.#names == null) { void(this.#names); }
 
         if (!wrap) { return; }
 
         // A wrapped Result is immutable
         Object.freeze(this);
 
         // Proxy indices and names so we can trap deferred errors
-        return new Proxy(this, {
+        const proxy = new Proxy(this, {
             get: (target, prop, receiver) => {
                 if (typeof(prop) === "string") {
 
@@ -127,6 +167,7 @@ export class Result extends Array<any> {
                 return Reflect.get(target, prop, receiver);
             }
         });
+        setNames(proxy, getNames(this));
     }
 
     /**
@@ -157,21 +198,14 @@ export class Result extends Array<any> {
      *  any outstanding deferred errors.
      */
     toObject(deep?: boolean): Record<string, any> {
-        return this.#names.reduce((accum, name, index) => {
-            assert(name != null, "value at index ${ index } unnamed", "UNSUPPORTED_OPERATION", {
+        const names = getNames(this);
+        return names.reduce((accum, name, index) => {
+
+            assert(name != null, `value at index ${ index } unnamed`, "UNSUPPORTED_OPERATION", {
                 operation: "toObject()"
             });
 
-            // Add values for names that don't conflict
-            if (!(name in accum)) {
-                let child = this.getValue(name);
-                if (deep && child instanceof Result) {
-                    child = child.toObject(deep);
-                }
-                accum[name] = child;
-            }
-
-            return accum;
+            return toObject(names, this, deep);
         }, <Record<string, any>>{});
     }
 
@@ -192,10 +226,12 @@ export class Result extends Array<any> {
         }
         if (end > this.length) { end = this.length; }
 
+        const _names = getNames(this);
+
         const result: Array<any> = [ ], names: Array<null | string> = [ ];
         for (let i = start; i < end; i++) {
             result.push(this[i]);
-            names.push(this.#names[i]);
+            names.push(_names[i]);
         }
 
         return new Result(_guard, result, names);
@@ -205,6 +241,8 @@ export class Result extends Array<any> {
      *  @_ignore
      */
     filter(callback: (el: any, index: number, array: Result) => boolean, thisArg?: any): Result {
+        const _names = getNames(this);
+
         const result: Array<any> = [ ], names: Array<null | string> = [ ];
         for (let i = 0; i < this.length; i++) {
             const item = this[i];
@@ -214,7 +252,7 @@ export class Result extends Array<any> {
 
             if (callback.call(thisArg, item, i, this)) {
                 result.push(item);
-                names.push(this.#names[i]);
+                names.push(_names[i]);
             }
         }
 
@@ -248,7 +286,7 @@ export class Result extends Array<any> {
      *  accessible by name.
      */
     getValue(name: string): any {
-        const index = this.#names.indexOf(name);
+        const index = getNames(this).indexOf(name);
         if (index === -1) { return undefined; }
 
         const value = this[index];