✨ feat: Refactor _remove as _erase via generic _concat.

Author: make-github-pseudonymous-again

src/_concat.js

@@ -8,8 +8,8 @@ import Node from './Node.js';
  * @param {Node} y First node of second input list.
  */
 export default function _concat(z, y) {
-	assert(z instanceof Node && z.next === null);
-	assert(y instanceof Node && y.prev === null);
+	assert(z instanceof Node);
+	assert(y instanceof Node);
 	z.next = y;
 	y.prev = z;
 }

src/_erase.js

@@ -0,0 +1,14 @@
+import assert from 'assert';
+import Node from './Node.js';
+import _concat from './_concat.js';
+
+/**
+ * Erase range [x, y) from list. Range cannot be empty.
+ *
+ * @param {Node} x Inclusive beginning of range to erase.
+ * @param {Node} y Exclusive end of range to erase.
+ */
+export default function _erase(x, y) {
+	assert(x instanceof Node);
+	_concat(x.prev, y);
+}

src/_remove.js

@@ -1,5 +1,6 @@
 import assert from 'assert';
 import Node from './Node.js';
+import _erase from './_erase.js';
 
 /**
  * Removes input {@link Node} from its list. Cannot be first or last, use
@@ -12,6 +13,5 @@ import Node from './Node.js';
  */
 export default function _remove(x) {
 	assert(x instanceof Node);
-	x.prev.next = x.next;
-	x.next.prev = x.prev;
+	_erase(x, x.next);
 }

src/index.js

@@ -1,5 +1,6 @@
 export {default as Node} from './Node.js';
 export {default as _concat} from './_concat.js';
+export {default as _erase} from './_erase.js';
 export {default as _extend} from './_extend.js';
 export {default as _iter} from './_iter.js';
 export {default as _iter_fast} from './_iter_fast.js';

test/src/remove.js

@@ -0,0 +1,11 @@
+import test from 'ava';
+
+import {list} from '@iterable-iterator/list';
+
+import {values, from, _remove} from '#module';
+
+test('_remove', (t) => {
+	const l = from('abc');
+	_remove(l.next);
+	t.is(list(values(l)).join(''), 'ac');
+});