wip: migrate to bun

test/flatten-methods.spec.ts

@@ -0,0 +1,104 @@
+import assert from 'node:assert';
+import lodashStable from 'lodash';
+import { args, _ } from './utils';
+import flatten from '../src/flatten';
+import flattenDeep from '../src/flattenDeep';
+import flattenDepth from '../src/flattenDepth';
+
+describe('flatten methods', () => {
+    const array = [1, [2, [3, [4]], 5]],
+        methodNames = ['flatten', 'flattenDeep', 'flattenDepth'];
+
+    it('should flatten `arguments` objects', () => {
+        const array = [args, [args]];
+
+        assert.deepStrictEqual(flatten(array), [1, 2, 3, args]);
+        assert.deepStrictEqual(flattenDeep(array), [1, 2, 3, 1, 2, 3]);
+        assert.deepStrictEqual(flattenDepth(array, 2), [1, 2, 3, 1, 2, 3]);
+    });
+
+    it('should treat sparse arrays as dense', () => {
+        const array = [[1, 2, 3], Array(3)],
+            expected = [1, 2, 3];
+
+        expected.push(undefined, undefined, undefined);
+
+        lodashStable.each(methodNames, (methodName) => {
+            const actual = _[methodName](array);
+            assert.deepStrictEqual(actual, expected);
+            assert.ok('4' in actual);
+        });
+    });
+
+    it('should flatten objects with a truthy `Symbol.isConcatSpreadable` value', () => {
+        if (Symbol && Symbol.isConcatSpreadable) {
+            const object = { '0': 'a', length: 1 },
+                array = [object],
+                expected = lodashStable.map(methodNames, lodashStable.constant(['a']));
+
+            object[Symbol.isConcatSpreadable] = true;
+
+            const actual = lodashStable.map(methodNames, (methodName) => _[methodName](array));
+
+            assert.deepStrictEqual(actual, expected);
+        }
+    });
+
+    it('should work with extremely large arrays', () => {
+        lodashStable.times(3, (index) => {
+            const expected = Array(5e5);
+            try {
+                let func = flatten;
+                if (index == 1) {
+                    func = flattenDeep;
+                } else if (index == 2) {
+                    func = flattenDepth;
+                }
+                assert.deepStrictEqual(func([expected]), expected);
+            } catch (e) {
+                assert.ok(false, e.message);
+            }
+        });
+    });
+
+    it('should work with empty arrays', () => {
+        const array = [[], [[]], [[], [[[]]]]];
+
+        assert.deepStrictEqual(flatten(array), [[], [], [[[]]]]);
+        assert.deepStrictEqual(flattenDeep(array), []);
+        assert.deepStrictEqual(flattenDepth(array, 2), [[[]]]);
+    });
+
+    it('should support flattening of nested arrays', () => {
+        assert.deepStrictEqual(flatten(array), [1, 2, [3, [4]], 5]);
+        assert.deepStrictEqual(flattenDeep(array), [1, 2, 3, 4, 5]);
+        assert.deepStrictEqual(flattenDepth(array, 2), [1, 2, 3, [4], 5]);
+    });
+
+    it('should return an empty array for non array-like objects', () => {
+        const expected = [],
+            nonArray = { '0': 'a' };
+
+        assert.deepStrictEqual(flatten(nonArray), expected);
+        assert.deepStrictEqual(flattenDeep(nonArray), expected);
+        assert.deepStrictEqual(flattenDepth(nonArray, 2), expected);
+    });
+
+    it('should return a wrapped value when chaining', () => {
+        let wrapped = _(array),
+            actual = wrapped.flatten();
+
+        assert.ok(actual instanceof _);
+        assert.deepEqual(actual.value(), [1, 2, [3, [4]], 5]);
+
+        actual = wrapped.flattenDeep();
+
+        assert.ok(actual instanceof _);
+        assert.deepEqual(actual.value(), [1, 2, 3, 4, 5]);
+
+        actual = wrapped.flattenDepth(2);
+
+        assert.ok(actual instanceof _);
+        assert.deepEqual(actual.value(), [1, 2, 3, [4], 5]);
+    });
+});