add range class

src/lib/Range.ts

@@ -0,0 +1,27 @@
+export class Range {
+	from;
+	to;
+
+	constructor(from: number, to: number) {
+		this.from = from;
+		this.to = to;
+	}
+
+	*[Symbol.iterator](): Generator<number, void, void> {
+		let index = this.from;
+		while (index < this.to) yield index++;
+	}
+
+	includes(n: number) {
+		return (n > this.from) && (n < this.to);
+	}
+}
+
+export function range(from: number, to: number) {
+	return new Range(from, to);
+}
+
+Deno.test("range", async () => {
+	const { assertEquals } = await import("https://deno.land/std@0.224.0/assert/assert_equals.ts");
+	assertEquals([...range(0, 4)], [0, 1, 2, 3]);
+});