chore: flatten src/ to root

utils/set.ts

@@ -0,0 +1,53 @@
+/**
+ * Note: this code is hot, so is optimized for speed.
+ */
+export function difference<A>(a: Set<A>, b: Set<A>): Set<A> {
+  const result = new Set<A>()
+  for (const item of a) {
+    if (!b.has(item)) {
+      result.add(item)
+    }
+  }
+  return result
+}
+
+/**
+ * Note: this code is hot, so is optimized for speed.
+ */
+export function intersects<A>(a: Set<A>, b: Set<A>): boolean {
+  if (a.size === 0 || b.size === 0) {
+    return false
+  }
+  for (const item of a) {
+    if (b.has(item)) {
+      return true
+    }
+  }
+  return false
+}
+
+/**
+ * Note: this code is hot, so is optimized for speed.
+ */
+export function every<A>(a: ReadonlySet<A>, b: ReadonlySet<A>): boolean {
+  for (const item of a) {
+    if (!b.has(item)) {
+      return false
+    }
+  }
+  return true
+}
+
+/**
+ * Note: this code is hot, so is optimized for speed.
+ */
+export function union<A>(a: Set<A>, b: Set<A>): Set<A> {
+  const result = new Set<A>()
+  for (const item of a) {
+    result.add(item)
+  }
+  for (const item of b) {
+    result.add(item)
+  }
+  return result
+}