JsonMap which can use json as a map key.

Author: nedtwigg

browser-extension/src/lib/jsonmap.ts

@@ -0,0 +1,67 @@
+/** Map which can take any JSON as key and uses its sorted serialization as the underlying key. */
+export class JsonMap<K, V> {
+  private map = new Map<string, V>()
+
+  set(key: K, value: V): this {
+    this.map.set(stableStringify(key), value)
+    return this
+  }
+
+  get(key: K): V | undefined {
+    return this.map.get(stableStringify(key))
+  }
+
+  has(key: K): boolean {
+    return this.map.has(stableStringify(key))
+  }
+
+  delete(key: K): boolean {
+    return this.map.delete(stableStringify(key))
+  }
+
+  clear(): void {
+    this.map.clear()
+  }
+
+  get size(): number {
+    return this.map.size
+  }
+
+  *values(): IterableIterator<V> {
+    yield* this.map.values()
+  }
+
+  *entries(): IterableIterator<[K, V]> {
+    for (const [stringKey, value] of this.map.entries()) {
+      yield [JSON.parse(stringKey) as K, value]
+    }
+  }
+
+  *keys(): IterableIterator<K> {
+    for (const stringKey of this.map.keys()) {
+      yield JSON.parse(stringKey) as K
+    }
+  }
+
+  [Symbol.iterator](): IterableIterator<[K, V]> {
+    return this.entries()
+  }
+}
+
+function stableStringify(v: unknown): string {
+  return JSON.stringify(v, (_k, val) => {
+    if (val && typeof val === 'object' && !Array.isArray(val)) {
+      // sort object keys recursively
+      return Object.keys(val as Record<string, unknown>)
+        .sort()
+        .reduce(
+          (acc, k) => {
+            ;(acc as any)[k] = (val as any)[k]
+            return acc
+          },
+          {} as Record<string, unknown>,
+        )
+    }
+    return val
+  })
+}