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eb39fafa4f
includes a (minimal) working wrapper Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
86 lines
2.0 KiB
Markdown
86 lines
2.0 KiB
Markdown
# enforce a maximum depth that callbacks can be nested (max-nested-callbacks)
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Many JavaScript libraries use the callback pattern to manage asynchronous operations. A program of any complexity will most likely need to manage several asynchronous operations at various levels of concurrency. A common pitfall that is easy to fall into is nesting callbacks, which makes code more difficult to read the deeper the callbacks are nested.
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```js
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foo(function () {
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bar(function () {
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baz(function() {
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qux(function () {
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});
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});
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});
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});
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```
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## Rule Details
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This rule enforces a maximum depth that callbacks can be nested to increase code clarity.
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## Options
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This rule has a number or object option:
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* `"max"` (default `10`) enforces a maximum depth that callbacks can be nested
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**Deprecated:** The object property `maximum` is deprecated; please use the object property `max` instead.
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### max
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Examples of **incorrect** code for this rule with the `{ "max": 3 }` option:
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```js
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/*eslint max-nested-callbacks: ["error", 3]*/
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foo1(function() {
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foo2(function() {
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foo3(function() {
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foo4(function() {
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// Do something
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});
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});
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});
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});
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```
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Examples of **correct** code for this rule with the `{ "max": 3 }` option:
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```js
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/*eslint max-nested-callbacks: ["error", 3]*/
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foo1(handleFoo1);
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function handleFoo1() {
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foo2(handleFoo2);
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}
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function handleFoo2() {
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foo3(handleFoo3);
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}
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function handleFoo3() {
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foo4(handleFoo4);
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}
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function handleFoo4() {
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foo5();
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}
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```
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## Further Reading
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* [Control flow in Node.js](http://book.mixu.net/node/ch7.html)
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* [Control Flow in Node](https://howtonode.org/control-flow)
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* [Control Flow in Node Part II](https://howtonode.org/control-flow-part-ii)
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## Related Rules
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* [complexity](complexity.md)
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* [max-depth](max-depth.md)
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* [max-len](max-len.md)
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* [max-lines](max-lines.md)
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* [max-lines-per-function](max-lines-per-function.md)
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* [max-params](max-params.md)
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* [max-statements](max-statements.md)
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