✨ feat: Show special props of TypedArray when showHidden is "always"

Author: Snowflyt

README.md

@@ -193,6 +193,7 @@ Aside from the features listed above, **showify** also supports many more specia
 **Collections:**
 
 - **Array:** `Array` objects are displayed as `[e1, e2, ...]`. Empty slots are displayed as `<${n} empty item${n === 1 ? "" : "s"}>`. For subclasses of `Array` or typed arrays, the `${className}` is displayed with its size, e.g., `MyArray(4) [1, <2 empty items>, 2, { foo: "bar" }]` or `Uint8Array(3) [1, 2, 3]`.
+- **Typed arrays:** Typed arrays (e.g., `Uint8Array`, `Int16Array`, etc.) are displayed as `${CtorName}(${length}) [v1, v2, ...]`. When `showHidden` is `"always"`, the following special properties are also displayed: `[BYTES_PER_ELEMENT]`, `[length]`, `[byteLength]`, `[byteOffset]`, and `[buffer]`.
 - **Long Arrays:** If `maxArrayLength` is set and the array has more elements than `maxArrayLength`, it is displayed as `[${e1}, ${e2}, ... ${n} more item${n === 1 ? "" : "s"}]`, e.g., `[1, 2, 3, 4, ... 2 more items]`.
 - **Map:** `Map` objects are displayed as `Map(${size}) { key1 => value1, key2 => value2, ... }`.
 - **Set:** `Set` objects are displayed as `Set(${size}) { value1, value2, ... }`.

packages/lite/README.md

@@ -22,4 +22,4 @@ The following features are removed from the original package:
 - ANSI color support.
 - `quoteStyle` is limited to `"single"` or `"double"`.
 - The `showHidden: "exclude-meta"` option for `show()`.
-- Special support for `ArrayBuffer`, `SharedArrayBuffer` and `DataView`.
+- Special support for `ArrayBuffer`, `SharedArrayBuffer`, `DataView`, and special properties of typed arrays.

src/index.ts

@@ -812,7 +812,21 @@ function buildTree(
         if (className !== "Array" && "length" in value && typeof value.length === "number")
           prefix = text(`${className}(${value.length})`);
         // Hide `length` property if `showHidden` is `exclude-meta`
-        if (showHidden === "exclude-meta") omittedKeys.add("length");
+        if (showHidden === "exclude-meta") {
+          omittedKeys.add("length");
+        } else if (
+          showHidden &&
+          showHidden !== "none" &&
+          // Show special properties for typed arrays
+          ArrayBuffer.isView(value) &&
+          !(value instanceof DataView)
+        ) {
+          pushExtraProperty("BYTES_PER_ELEMENT", (value as Uint8Array).BYTES_PER_ELEMENT);
+          pushExtraProperty("length", (value as Uint8Array).length);
+          pushExtraProperty("byteLength", value.byteLength);
+          pushExtraProperty("byteOffset", value.byteOffset);
+          pushExtraProperty("buffer", value.buffer);
+        }
       }
 
       // Wrapper objects for primitives
@@ -894,14 +908,17 @@ function buildTree(
           ),
         );
 
-      const formatKey = (key: string | symbol): string =>
-        typeof key === "symbol" ? c.symbol(key.toString())
-          // Always quote keys if `quoteKeys` is set to `"always"`
-        : quoteKeys === "always" ? c.string(stringifyString(key, quoteStyle))
-          // For string keys that are valid identifiers, we should show them as is
-        : /^[A-Za-z_$][A-Za-z0-9_$]*$/.test(key) ? key
-          // For other string keys, we should wrap them with quotes
-        : c.string(stringifyString(key, quoteStyle));
+      function formatKey(key: string | symbol): string {
+        return (
+          typeof key === "symbol" ? c.symbol(key.toString())
+            // Always quote keys if `quoteKeys` is set to `"always"`
+          : quoteKeys === "always" ? c.string(stringifyString(key, quoteStyle))
+            // For string keys that are valid identifiers, we should show them as is
+          : /^[A-Za-z_$][A-Za-z0-9_$]*$/.test(key) ? key
+            // For other string keys, we should wrap them with quotes
+          : c.string(stringifyString(key, quoteStyle))
+        );
+      }
 
       // Object key/value pair
       const objectEntries = otherKeys.map((key) => {

test/array.spec.ts

@@ -248,4 +248,23 @@ describe("Array", () => {
       util.inspect([1, 2, 3], { showHidden: true, colors: true }),
     );
   });
+
+  it('should show special properties of typed arrays when `showHidden` is not `"none"`', () => {
+    const arr = new Uint8Array([1, 2, 3]);
+
+    expect(show(arr, { showHidden: "exclude-meta" })).toEqual("Uint8Array(3) [1, 2, 3]");
+
+    expect(show(arr, { showHidden: "always" })).toEqual(
+      "Uint8Array(3) [1, 2, 3, [BYTES_PER_ELEMENT]: 1, [length]: 3, [byteLength]: 3, [byteOffset]: 0, [buffer]: ArrayBuffer { [Uint8Contents]: <01 02 03>, [byteLength]: 3 }]",
+    );
+    expect(inspect(arr, { showHidden: "always" })).toEqual(
+      util
+        .inspect(arr, { showHidden: true })
+        // util.inspect does not show [Uint8Contents] for ArrayBuffer, seems to be BUG
+        .replace(
+          "ArrayBuffer { [byteLength]: 3 }",
+          "ArrayBuffer { [Uint8Contents]: <01 02 03>, [byteLength]: 3 }",
+        ),
+    );
+  });
 });