refactored funcitons to use sets.shift() & for .. of (#43)

* shift sets

Also: removed nullish coalescing & renamed result to resultSet

* for (const set of sets)

src/comparisons/disjoint.function.ts

@@ -15,9 +15,9 @@ export function disjoint<T, S extends ReadonlySet<T>>(...sets: S[]): boolean {
 		return true;
 	}
 
-	const allElements = new Set<T>(sets[0]);
-	for (let index = 1; index < sets.length; index++) {
-		for (const element of sets[index]!) {
+	const allElements = new Set<T>(sets.shift());
+	for (const set of sets) {
+		for (const element of set) {
 			if (allElements.has(element)) {
 				return false;
 			} else {

src/comparisons/equivalence.function.ts

@@ -25,9 +25,10 @@ export function equivalence<T, S extends ReadonlySet<T>>(...sets: S[]): boolean
 		return false;
 	}
 
-	for (const element of sets[0]!) {
-		for (let index = 1; index < sets.length; index++) {
-			if (!sets[index]?.has(element)) {
+	const primarySet = sets.shift()!;
+	for (const element of primarySet) {
+		for (const set of sets) {
+			if (!set.has(element)) {
 				return false;
 			}
 		}

src/comparisons/proper-subset.function.ts

@@ -25,9 +25,10 @@ export function properSubset<T, S extends ReadonlySet<T>>(...sets: S[]): boolean
 		return false;
 	}
 
-	for (const element of sets[0]!) {
-		for (let index = 1; index < sets.length; index++) {
-			if (!sets[index]?.has(element)) {
+	const primarySet = sets.shift()!;
+	for (const element of primarySet) {
+		for (const set of sets) {
+			if (!set.has(element)) {
 				return false;
 			}
 		}

src/comparisons/proper-superset.function.ts

@@ -25,9 +25,10 @@ export function properSuperset<T, S extends ReadonlySet<T>>(...sets: S[]): boole
 		return false;
 	}
 
-	for (let index = 1; index < sets.length; index++) {
-		for (const element of sets[index]!) {
-			if (!sets[0]?.has(element)) {
+	const primarySet = sets.shift()!;
+	for (const set of sets) {
+		for (const element of set) {
+			if (!primarySet.has(element)) {
 				return false;
 			}
 		}

src/comparisons/subset.function.ts

@@ -24,9 +24,10 @@ export function subset<T, S extends ReadonlySet<T>>(...sets: S[]): boolean {
 		return false;
 	}
 
-	for (const element of sets[0]!) {
-		for (let index = 1; index < sets.length; index++) {
-			if (!sets[index]?.has(element)) {
+	const primarySet = sets.shift()!;
+	for (const element of primarySet) {
+		for (const set of sets) {
+			if (!set.has(element)) {
 				return false;
 			}
 		}

src/comparisons/superset.function.ts

@@ -26,9 +26,10 @@ export function superset<T, S extends ReadonlySet<T>>(...sets: S[]): boolean {
 		return false;
 	}
 
-	for (let index = 1; index < sets.length; index++) {
-		for (const element of sets[index]!) {
-			if (!sets[0]?.has(element)) {
+	const primarySet = sets.shift()!;
+	for (const set of sets) {
+		for (const element of set) {
+			if (!primarySet.has(element)) {
 				return false;
 			}
 		}

src/operations/difference.function.ts

@@ -11,13 +11,13 @@ export function difference<T>(...sets: ReadonlySet<T>[]): ReadonlySet<T>;
  * @description A ∖ B ≔ { x : (x ∈ A) ∧ (x ∉ B) }
  */
 export function difference<T, S extends ReadonlySet<T>>(...sets: S[]): S {
-	const result = new Set<T>(sets[0]);
+	const resultSet = new Set<T>(sets.shift());
 
-	for (let index = 1; index < sets.length; index++) {
-		for (const element of sets[index]!) {
-			result.delete(element);
+	for (const set of sets) {
+		for (const element of set) {
+			resultSet.delete(element);
 		}
 	}
 
-	return result as ReadonlySet<T> as S;
+	return resultSet as ReadonlySet<T> as S;
 }

src/operations/intersection.function.ts

@@ -9,15 +9,15 @@ export function intersection<T>(...sets: ReadonlySet<T>[]): ReadonlySet<T>;
  * @description A ∩ B ≔ { x : (x ∈ A) ∧ (x ∈ B) }
  */
 export function intersection<T, S extends ReadonlySet<T>>(...sets: S[]): S {
-	const result = new Set<T>(sets[0]);
+	const resultSet = new Set<T>(sets.shift());
 
-	for (let index = 1; index < sets.length; index++) {
-		for (const element of result) {
-			if (!sets[index]!.has(element)) {
-				result.delete(element);
+	for (const set of sets) {
+		for (const element of resultSet) {
+			if (!set.has(element)) {
+				resultSet.delete(element);
 			}
 		}
 	}
 
-	return result as ReadonlySet<T> as S;
+	return resultSet as ReadonlySet<T> as S;
 }

src/operations/union.function.ts

@@ -9,13 +9,13 @@ export function union<T>(...sets: ReadonlySet<T>[]): ReadonlySet<T>;
  * @description A ∪ B ≔ { x : (x ∈ A) ∨ (x ∈ B) }
  */
 export function union<T, S extends ReadonlySet<T>>(...sets: S[]): S {
-	const result = new Set<T>(sets[0]);
+	const resultSet = new Set<T>(sets.shift());
 
-	for (let index = 1; index < sets.length; index++) {
-		for (const element of sets[index]!) {
-			result.add(element);
+	for (const set of sets) {
+		for (const element of set) {
+			resultSet.add(element);
 		}
 	}
 
-	return result as ReadonlySet<T> as S;
+	return resultSet as ReadonlySet<T> as S;
 }

src/operations/xor.function.ts

@@ -11,19 +11,19 @@ export function xor<T>(...sets: ReadonlySet<T>[]): ReadonlySet<T>;
  * @description A ∆ B ≔ { x : (x ∈ A) ⊕ (x ∈ B) }
  */
 export function xor<T, S extends ReadonlySet<T>>(...sets: S[]): S {
-	const result = new Set<T>(sets[0]);
+	const resultSet = new Set<T>(sets.shift());
 	const reusedElements = new Set<T>();
 
-	for (let index = 1; index < sets.length; index++) {
-		for (const element of sets[index]!) {
-			if (result.has(element)) {
-				result.delete(element);
+	for (const set of sets) {
+		for (const element of set) {
+			if (resultSet.has(element)) {
+				resultSet.delete(element);
 				reusedElements.add(element);
 			} else if (!reusedElements.has(element)) {
-				result.add(element);
+				resultSet.add(element);
 			}
 		}
 	}
 
-	return result as ReadonlySet<T> as S;
+	return resultSet as ReadonlySet<T> as S;
 }