From eec483093df7075cc94f686b1440f0dcfd76f466 Mon Sep 17 00:00:00 2001
From: EuAndreh <eu@euandre.org>
Date: Fri, 11 Jul 2025 18:37:47 -0300
Subject: src/sjs.mjs: Add reductions()

---
 tests/sjs.mjs | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)

(limited to 'tests/sjs.mjs')

diff --git a/tests/sjs.mjs b/tests/sjs.mjs
index c8f52dd..9376429 100644
--- a/tests/sjs.mjs
+++ b/tests/sjs.mjs
@@ -32,6 +32,8 @@ import {
 	reduced,
 	reduceRec,
 	reduce,
+	reductionsRec,
+	reductions,
 	mapValues,
 	repeat,
 	runTests,
@@ -958,6 +960,72 @@ const test_reduce = t => {
 	});
 };
 
+const test_reductionsRec = t => {
+	t.start("reductionsRec()");
+
+	t.testing("return the value if isReduced()", () => {
+		t.assertEq(
+			reductionsRec(null, null, reduced("abc"), null, []),
+			["abc"],
+		);
+	});
+
+	t.testing("the bare value if at the end of the collection", () => {
+		t.assertEq(reductionsRec([],     null, null, 0, "ret"), "ret");
+		t.assertEq(reductionsRec([1, 2], null, null, 2, "ret"), "ret");
+	});
+
+	t.testing("recurse while applying function", () => {
+		const expected = [{
+			acc:   -5,
+			el:    4,
+			index: 3,
+			coll:  [1, 2, 3, 4, 5],
+			ret:   -1,
+		}, {
+			acc:   -1,
+			el:    5,
+			index: 4,
+			coll:  [1, 2, 3, 4, 5],
+			ret:   4,
+		}];
+		const calls = [];
+		const fn = (acc, el, index, coll) => {
+			const ret = acc + el;
+			calls.push({
+				acc,
+				el,
+				index,
+				coll,
+				ret,
+			});
+			return ret;
+		};
+		const coll = [1, 2, 3, 4, 5];
+		t.assertEq(reductionsRec(coll, fn, -5, 3, []), [-1, 4]);
+		t.assertEq(calls, expected);
+	});
+};
+
+const test_reductions = t => {
+	t.start("reductions()");
+
+	const add = (a, b) => a + b;
+
+
+	t.testing("with and without initial values", () => {
+		t.assertEq(reductions([1, 1, 1, 1], add), [1, 2, 3, 4]);
+		t.assertEq(reductions([1, 1, 1], add, 0), [1, 2, 3]);
+		t.assertEq(reductions([1, 1, 1], add, 1), [2, 3, 4]);
+		t.assertEq(reductions([1, 2, 3], add), [1, 3, 6]);
+	});
+
+	t.testing("the last values corresponds to reduce()", () => {
+		const arr = [1, 2, 3];
+		t.assertEq(last(reductions(arr, add)), reduce(arr, add));
+	});
+};
+
 const test_mapValues = t => {
 	t.start("mapValues()");
 
@@ -1021,6 +1089,8 @@ runTests([
 	test_reduced,
 	test_reduceRec,
 	test_reduce,
+	test_reductionsRec,
+	test_reductions,
 	test_mapValues,
 	test_repeat,
 ]);
-- 
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