1 files changed, 83 insertions, 0 deletions
diff --git a/dom/webgpu/tests/cts/checkout/src/common/internal/query/json_param_value.ts b/dom/webgpu/tests/cts/checkout/src/common/internal/query/json_param_value.ts
new file mode 100644
index 0000000000..f4be7642d3
--- /dev/null
+++ b/dom/webgpu/tests/cts/checkout/src/common/internal/query/json_param_value.ts
@@ -0,0 +1,83 @@
+import { assert, sortObjectByKey } from '../../util/util.js';
+import { JSONWithUndefined } from '../params_utils.js';
+
+// JSON can't represent various values and by default stores them as `null`.
+// Instead, storing them as a magic string values in JSON.
+const jsUndefinedMagicValue = '_undef_';
+const jsNaNMagicValue = '_nan_';
+const jsPositiveInfinityMagicValue = '_posinfinity_';
+const jsNegativeInfinityMagicValue = '_neginfinity_';
+
+// -0 needs to be handled separately, because -0 === +0 returns true. Not
+// special casing +0/0, since it behaves intuitively. Assuming that if -0 is
+// being used, the differentiation from +0 is desired.
+const jsNegativeZeroMagicValue = '_negzero_';
+
+const toStringMagicValue = new Map<unknown, string>([
+  [undefined, jsUndefinedMagicValue],
+  [NaN, jsNaNMagicValue],
+  [Number.POSITIVE_INFINITY, jsPositiveInfinityMagicValue],
+  [Number.NEGATIVE_INFINITY, jsNegativeInfinityMagicValue],
+  // No -0 handling because it is special cased.
+]);
+
+const fromStringMagicValue = new Map<string, unknown>([
+  [jsUndefinedMagicValue, undefined],
+  [jsNaNMagicValue, NaN],
+  [jsPositiveInfinityMagicValue, Number.POSITIVE_INFINITY],
+  [jsNegativeInfinityMagicValue, Number.NEGATIVE_INFINITY],
+  // -0 is handled in this direction because there is no comparison issue.
+  [jsNegativeZeroMagicValue, -0],
+]);
+
+function stringifyFilter(k: string, v: unknown): unknown {
+  // Make sure no one actually uses a magic value as a parameter.
+  if (typeof v === 'string') {
+    assert(
+      !fromStringMagicValue.has(v),
+      `${v} is a magic value for stringification, so cannot be used`
+    );
+
+    assert(
+      v !== jsNegativeZeroMagicValue,
+      `${v} is a magic value for stringification, so cannot be used`
+    );
+  }
+
+  if (Object.is(v, -0)) {
+    return jsNegativeZeroMagicValue;
+  }
+
+  return toStringMagicValue.has(v) ? toStringMagicValue.get(v) : v;
+}
+
+export function stringifyParamValue(value: JSONWithUndefined): string {
+  return JSON.stringify(value, stringifyFilter);
+}
+
+/**
+ * Like stringifyParamValue but sorts dictionaries by key, for hashing.
+ */
+export function stringifyParamValueUniquely(value: JSONWithUndefined): string {
+  return JSON.stringify(value, (k, v) => {
+    if (typeof v === 'object' && v !== null) {
+      return sortObjectByKey(v);
+    }
+
+    return stringifyFilter(k, v);
+  });
+}
+
+// 'any' is part of the JSON.parse reviver interface, so cannot be avoided.
+// eslint-disable-next-line  @typescript-eslint/no-explicit-any
+function parseParamValueReviver(k: string, v: any): any {
+  if (fromStringMagicValue.has(v)) {
+    return fromStringMagicValue.get(v);
+  }
+
+  return v;
+}
+
+export function parseParamValue(s: string): JSONWithUndefined {
+  return JSON.parse(s, parseParamValueReviver);
+}