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Eslint参考手册

规则 | Rules

no-useless-concat

没有必要将两个字符串连接在一起,例如:

var foo = "a" + "b";

此代码很可能是重构的结果,其中一个变量已从连接中移除(如"a" + b + "b")。在这种情况下,级联并不重要,代码可以重写为:

var foo = "ab";

规则细节

这条规则旨在标记2个文字的连接,当它们可以合并成一个文字时。文字可以是字符串或模板文字。

此规则的错误代码示例:

/*eslint no-useless-concat: "error"*/
/*eslint-env es6*/

// these are the same as "10"
var a = `some` + `string`;
var a = '1' + '0';
var a = '1' + `0`;
var a = `1` + '0';
var a = `1` + `0`;

此规则的正确代码示例:

/*eslint no-useless-concat: "error"*/

// when a non string is included
var c = a + b;
var c = '1' + a;
var a = 1 + '1';
var c = 1 - 2;
// when the string concatenation is multiline
var c = "foo" +
    "bar";

何时不使用它

如果您不希望收到关于不必要的字符串串联的通知,则可以安全地禁用此规则。

版本

该规则在 ESLint 1.3.0中引入。

资源

  • Rule source
  • Documentation source

规则 | Rules相关

1.accessor-pairs
2.array-bracket-newline
3.array-bracket-spacing
4.array-callback-return
5.array-element-newline
6.arrow-body-style
7.arrow-parens
8.arrow-spacing
9.block-scoped-var
10.block-spacing
11.brace-style
12.callback-return
13.camelcase
14.capitalized-comments
15.class-methods-use-this
16.comma-dangle
17.comma-spacing
18.comma-style
19.complexity
20.computed-property-spacing
21.consistent-return
22.consistent-this
23.constructor-super
24.curly
25.default-case
26.dot-location
27.dot-notation
28.eol-last
29.eqeqeq
30.for-direction
31.func-call-spacing
32.func-name-matching
33.func-names
34.func-style
35.function-paren-newline
36.generator-star
37.generator-star-spacing
38.getter-return
39.global-require
40.global-strict
41.guard-for-in
42.handle-callback-err
43.id-blacklist
44.id-length
45.id-match
46.implicit-arrow-linebreak
47.indent
48.indent-legacy
49.init-declarations
50.jsx-quotes
51.key-spacing
52.keyword-spacing
53.line-comment-position
54.linebreak-style
55.lines-around-comment
56.lines-around-directive
57.lines-between-class-members
58.max-depth
59.max-len
60.max-lines
61.max-nested-callbacks
62.max-params
63.max-statements
64.max-statements-per-line
65.multiline-comment-style
66.multiline-ternary
67.new-cap
68.new-parens
69.newline-after-var
70.newline-before-return
71.newline-per-chained-call
72.no-alert
73.no-array-constructor
74.no-arrow-condition
75.no-await-in-loop
76.no-bitwise
77.no-buffer-constructor
78.no-caller
79.no-case-declarations
80.no-catch-shadow
81.no-class-assign
82.no-comma-dangle
83.no-compare-neg-zero
84.no-cond-assign
85.no-confusing-arrow
86.no-console
87.no-const-assign
88.no-constant-condition
89.no-continue
90.no-control-regex
91.no-debugger
92.no-delete-var
93.no-div-regex
94.no-dupe-args
95.no-dupe-class-members
96.no-dupe-keys
97.no-duplicate-case
98.no-duplicate-imports
99.no-else-return
100.no-empty
Eslint

ESLint 是一个代码规范和错误检查工具,有以下几个特性。所有东西都是可以插拔的。你可以调用任意的 rule api 或者 formatter api 去打包或者定义 rule or formatter。任意的 rule 都是独立的。没有特定的 coding style,你可以自己配置。

主页 https://eslint.org/
源码 https://github.com/eslint/eslint
发布版本 4.12.0

Eslint目录

1.指南 | Guide
2.规则 | Rules