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eb39fafa4f
includes a (minimal) working wrapper Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
159 lines
4.2 KiB
Markdown
159 lines
4.2 KiB
Markdown
# enforce the location of single-line statements (nonblock-statement-body-position)
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When writing `if`, `else`, `while`, `do-while`, and `for` statements, the body can be a single statement instead of a block. It can be useful to enforce a consistent location for these single statements.
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For example, some developers avoid writing code like this:
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```js
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if (foo)
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bar();
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```
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If another developer attempts to add `baz();` to the `if` statement, they might mistakenly change the code to
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```js
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if (foo)
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bar();
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baz(); // this line is not in the `if` statement!
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```
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To avoid this issue, one might require all single-line `if` statements to appear directly after the conditional, without a linebreak:
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```js
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if (foo) bar();
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```
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## Rule Details
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This rule aims to enforce a consistent location for single-line statements.
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Note that this rule does not enforce the usage of single-line statements in general. If you would like to disallow single-line statements, use the [`curly`](/docs/rules/curly.md) rule instead.
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### Options
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This rule accepts a string option:
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* `"beside"` (default) disallows a newline before a single-line statement.
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* `"below"` requires a newline before a single-line statement.
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* `"any"` does not enforce the position of a single-line statement.
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Additionally, the rule accepts an optional object option with an `"overrides"` key. This can be used to specify a location for particular statements that override the default. For example:
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* `"beside", { "overrides": { "while": "below" } }` requires all single-line statements to appear on the same line as their parent, unless the parent is a `while` statement, in which case the single-line statement must not be on the same line.
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* `"below", { "overrides": { "do": "any" } }` disallows all single-line statements from appearing on the same line as their parent, unless the parent is a `do-while` statement, in which case the position of the single-line statement is not enforced.
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Examples of **incorrect** code for this rule with the default `"beside"` option:
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```js
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/* eslint nonblock-statement-body-position: ["error", "beside"] */
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if (foo)
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bar();
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else
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baz();
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while (foo)
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bar();
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for (let i = 1; i < foo; i++)
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bar();
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do
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bar();
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while (foo)
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```
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Examples of **correct** code for this rule with the default `"beside"` option:
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```js
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/* eslint nonblock-statement-body-position: ["error", "beside"] */
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if (foo) bar();
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else baz();
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while (foo) bar();
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for (let i = 1; i < foo; i++) bar();
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do bar(); while (foo)
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if (foo) { // block statements are always allowed with this rule
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bar();
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} else {
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baz();
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}
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```
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Examples of **incorrect** code for this rule with the `"below"` option:
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```js
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/* eslint nonblock-statement-body-position: ["error", "below"] */
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if (foo) bar();
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else baz();
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while (foo) bar();
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for (let i = 1; i < foo; i++) bar();
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do bar(); while (foo)
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```
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Examples of **correct** code for this rule with the `"below"` option:
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```js
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/* eslint nonblock-statement-body-position: ["error", "below"] */
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if (foo)
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bar();
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else
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baz();
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while (foo)
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bar();
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for (let i = 1; i < foo; i++)
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bar();
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do
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bar();
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while (foo)
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if (foo) {
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// Although the second `if` statement is on the same line as the `else`, this is a very common
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// pattern, so it's not checked by this rule.
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} else if (bar) {
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}
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```
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Examples of **incorrect** code for this rule with the `"beside", { "overrides": { "while": "below" } }` rule:
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```js
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/* eslint nonblock-statement-body-position: ["error", "beside", { "overrides": { "while": "below" } }] */
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if (foo)
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bar();
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while (foo) bar();
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```
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Examples of **correct** code for this rule with the `"beside", { "overrides": { "while": "below" } }` rule:
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```js
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/* eslint nonblock-statement-body-position: ["error", "beside", { "overrides": { "while": "below" } }] */
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if (foo) bar();
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while (foo)
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bar();
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```
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## When Not To Use It
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If you're not concerned about consistent locations of single-line statements, you should not turn on this rule. You can also disable this rule if you're using the `"all"` option for the [`curly`](/docs/rules/curly.md) rule, because this will disallow single-line statements entirely.
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## Further Reading
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* JSCS: [requireNewlineBeforeSingleStatementsInIf](https://jscs-dev.github.io/rule/requireNewlineBeforeSingleStatementsInIf)
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