test: add common.getArrayBufferViews(buf)

PR-URL: https://github.com/nodejs/node/pull/12223
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

test/README.md

@@ -220,6 +220,12 @@ The expected error should be [subclassed by the `internal/errors` module](https:
 
 Tests whether `name` and `expected` are part of a raised warning.
 
+## getArrayBufferViews(buf)
+* `buf` [<Buffer>](https://nodejs.org/api/buffer.html#buffer_class_buffer)
+* return [<ArrayBufferView[]>](https://developer.mozilla.org/en-US/docs/Web/API/ArrayBufferView)
+
+Returns an instance of all possible `ArrayBufferView`s of the provided Buffer.
+
 ### hasCrypto
 * return [<Boolean>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type)
 

test/common.js

@@ -654,3 +654,29 @@ exports.skipIfInspectorDisabled = function skipIfInspectorDisabled() {
     process.exit(0);
   }
 };
+
+const arrayBufferViews = [
+  Int8Array,
+  Uint8Array,
+  Uint8ClampedArray,
+  Int16Array,
+  Uint16Array,
+  Int32Array,
+  Uint32Array,
+  Float32Array,
+  Float64Array,
+  DataView
+];
+
+exports.getArrayBufferViews = function getArrayBufferViews(buf) {
+  const { buffer, byteOffset, byteLength } = buf;
+
+  const out = [];
+  for (const type of arrayBufferViews) {
+    const { BYTES_PER_ELEMENT = 1 } = type;
+    if (byteLength % BYTES_PER_ELEMENT === 0) {
+      out.push(new type(buffer, byteOffset, byteLength / BYTES_PER_ELEMENT));
+    }
+  }
+  return out;
+};