feat(iterate): add function to limit iteration

Author: Shil Sinha

iterUtils.js

@@ -1,3 +1,4 @@
+const assert = require('assert');
 const sift = require('sift').default;
 
 /**
@@ -15,6 +16,17 @@ async function *filterIt(filter, iter) {
   }
 }
 
+async function *limitIt(limit, iter) {
+  let count = 0;
+  for await (const item of iter) {
+    yield item;
+
+    if (++count === limit) {
+      break
+    }
+  }
+}
+
 /**
  * @template T
  * @implements AsyncIterable<T>
@@ -61,6 +73,15 @@ class DecoratedIterable {
     }
     return result;
   }
+
+  /**
+   * @param {number} limit
+   * @return {DecoratedIterable<T>}
+   */
+  limit(limit) {
+    assert(limit && typeof limit === 'number', '"limit" must be a positive integer');
+    return new DecoratedIterable(limitIt(limit, this));
+  }
 }
 
 module.exports = {
@@ -73,4 +94,4 @@ module.exports = {
   decorateIt(iter) {
     return new DecoratedIterable(iter);
   }
-};
+};