Docs: Add docs for QUnit.dump.setParser() and up/down/join helpers

docs/api/extension/QUnit.dump.parse.md

@@ -22,7 +22,7 @@ Extensible data dumping and string serialization.
 
 This method does string serialization by parsing data structures and objects. It parses DOM elements to a string representation of their outer HTML. By default, nested structures will be displayed up to five levels deep. Anything beyond that is replaced by `[object Object]` and `[object Array]` placeholders.
 
-If you need more or less output, change the value of `QUnit.config.maxDepth`, representing how deep the elements should be parsed.
+If you need more or less output, change the value of [`QUnit.config.maxDepth`](../config/maxDepth.md), representing how deep the elements should be parsed.
 
 ## Changelog
 

docs/api/extension/QUnit.dump.setParser.md

@@ -0,0 +1,116 @@
+---
+layout: page-api
+title: QUnit.dump.setParser()
+excerpt: Override string serialization for a given data type.
+groups:
+  - extension
+redirect_from:
+  - "/extension/QUnit.dump.setParser/"
+version_added: "1.0.0"
+---
+
+`QUnit.dump.setParser( name, parser )`
+
+Override string serialization in [`QUnit.dump.parse()`](./QUnit.dump.parse.md) for a given data type.
+
+| name | description |
+|------|-------------|
+| `name` (string) | Value type |
+| `parser` (function) | Value formatter callback |
+
+Value type is one of the following:
+
+* `array`
+* `bigint` (ES2020, determined by native `typeof`)
+* `boolean`
+* `date`
+* `document`
+* `error`
+* `function`
+* `node`
+* `null`
+* `number`
+* `object`
+* `regexp`
+* `string`
+* `symbol` (ES2019, determined by native `typeof`)
+* `undefined`
+* `window`
+
+If your callback allows recursion into arbitrary child value structures, you may call [`QUnit.dump.parse()`](./QUnit.dump.parse.md) recursively. Recursive callers must pass on the stack, and call `QUnit.dump.up()` to increase depth tracking beforehand, and `QUnit.dump.down()` to decrease it afterward.
+
+If your value type may contain any number of children (such as an object or array, something not limited to being formatted on a short single line), check the depth against [`QUnit.config.maxDepth`](../config/maxDepth.md), and return a type-specific placeholder value if the depth limit was exceeded.
+
+You may use `QUnit.dump.join()` to aid in automatic formatting of indentation based on the current depth. Refer to examples below.
+
+## Changelog
+
+| [QUnit 2.1](https://github.com/qunitjs/qunit/releases/tag/2.1.0) | The `QUnit.jsDump` alias was removed.
+| [QUnit 1.15](https://github.com/qunitjs/qunit/releases/tag/1.15.0) | The `QUnit.jsDump` interface was renamed to `QUnit.dump`.<br/>The `QUnit.jsDump` alias is deprecated.
+
+## Examples
+
+### Value formatter
+
+```js
+QUnit.dump.setParser('document', function (doc) {
+  return '[Document ' + doc.location.href + ']';
+});
+```
+
+```js
+var example = { foo: document.createElement('div') };
+
+var dumped1 = QUnit.dump.parse(example);
+console.log(dumped1);
+// # Default
+// {
+//   "foo": <div></div>
+// }
+
+QUnit.dump.setParser('node', function (obj) {
+  return '[Node ' + obj.nodeName.toLowerCase() + ']';
+});
+
+var dumped2 = QUnit.dump.parse(example);
+console.log(dumped2);
+// # Custom
+// {
+//   "foo": [Node div]
+// }
+```
+
+### Deep formatter
+
+```js
+QUnit.dump.setParser('array', function (arr, stack) {
+    if (QUnit.config.maxDepth && QUnit.dump.depth > QUnit.config.maxDepth) {
+      return '[object Array]';
+    }
+
+    QUnit.dump.up();
+
+    let i = arr.length;
+    const ret = new Array(i);
+    while (i--) {
+      ret[i] = QUnit.dump.parse(arr[i], undefined, stack);
+    }
+
+    QUnit.dump.down();
+
+    return QUnit.dump.join('[', ret, ']');
+    // Output:
+    // 1. 'pre' text.
+    // 2. for each value:
+    //    - line break and inner indentation
+    //    - value as-is
+    //    - comma (if not last)
+    // 3. line break and outer indentation (if any)
+    // 4. 'post' text
+    //
+    // [
+    //   "foo",
+    //   "bar"
+    // ]
+  }
+```