projects / pve-eslint.git / blame
| Commit | Line | Data |
|---|---|---|
| eb39fafa DC |
1 | # require an empty line before `return` statements (newline-before-return) |
| 2 | ||
| 3 | This rule was **deprecated** in ESLint v4.0.0 and replaced by the [padding-line-between-statements](padding-line-between-statements.md) rule. | |
| 4 | ||
| 5 | There is no hard and fast rule about whether empty lines should precede `return` statements in JavaScript. However, clearly delineating where a function is returning can greatly increase the readability and clarity of the code. For example: | |
| 6 | ||
| 7 | ```js | |
| 8 | function foo(bar) { | |
| 9 | var baz = 'baz'; | |
| 10 | if (!bar) { | |
| 11 | bar = baz; | |
| 12 | return bar; | |
| 13 | } | |
| 14 | return bar; | |
| 15 | } | |
| 16 | ``` | |
| 17 | ||
| 18 | Adding newlines visibly separates the return statements from the previous lines, making it clear where the function exits and what value it returns: | |
| 19 | ||
| 20 | ```js | |
| 21 | function foo(bar) { | |
| 22 | var baz = 'baz'; | |
| 23 | ||
| 24 | if (!bar) { | |
| 25 | bar = baz; | |
| 26 | ||
| 27 | return bar; | |
| 28 | } | |
| 29 | ||
| 30 | return bar; | |
| 31 | } | |
| 32 | ``` | |
| 33 | ||
| 34 | ## Rule Details | |
| 35 | ||
| 36 | This rule requires an empty line before `return` statements to increase code clarity, except when the `return` is alone inside a statement group (such as an if statement). In the latter case, the `return` statement does not need to be delineated by virtue of it being alone. Comments are ignored and do not count as empty lines. | |
| 37 | ||
| 38 | Examples of **incorrect** code for this rule: | |
| 39 | ||
| 40 | ```js | |
| 41 | /*eslint newline-before-return: "error"*/ | |
| 42 | ||
| 43 | function foo(bar) { | |
| 44 | if (!bar) { | |
| 45 | return; | |
| 46 | } | |
| 47 | return bar; | |
| 48 | } | |
| 49 | ||
| 50 | function foo(bar) { | |
| 51 | if (!bar) { | |
| 52 | return; | |
| 53 | } | |
| 54 | /* multi-line | |
| 55 | comment */ | |
| 56 | return bar; | |
| 57 | } | |
| 58 | ``` | |
| 59 | ||
| 60 | Examples of **correct** code for this rule: | |
| 61 | ||
| 62 | ```js | |
| 63 | /*eslint newline-before-return: "error"*/ | |
| 64 | ||
| 65 | function foo() { | |
| 66 | return; | |
| 67 | } | |
| 68 | ||
| 69 | function foo() { | |
| 70 | ||
| 71 | return; | |
| 72 | } | |
| 73 | ||
| 74 | function foo(bar) { | |
| 75 | if (!bar) return; | |
| 76 | } | |
| 77 | ||
| 78 | function foo(bar) { | |
| 79 | if (!bar) { return }; | |
| 80 | } | |
| 81 | ||
| 82 | function foo(bar) { | |
| 83 | if (!bar) { | |
| 84 | return; | |
| 85 | } | |
| 86 | } | |
| 87 | ||
| 88 | function foo(bar) { | |
| 89 | if (!bar) { | |
| 90 | return; | |
| 91 | } | |
| 92 | ||
| 93 | return bar; | |
| 94 | } | |
| 95 | ||
| 96 | function foo(bar) { | |
| 97 | if (!bar) { | |
| 98 | ||
| 99 | return; | |
| 100 | } | |
| 101 | } | |
| 102 | ||
| 103 | function foo() { | |
| 104 | ||
| 105 | // comment | |
| 106 | return; | |
| 107 | } | |
| 108 | ``` | |
| 109 | ||
| 110 | ## When Not To Use It | |
| 111 | ||
| 112 | You can safely disable this rule if you do not have any strict conventions about whitespace before `return` statements. | |
| 113 | ||
| 114 | ## Related Rules | |
| 115 | ||
| 116 | * [newline-after-var](newline-after-var.md) |