eslint/docs/src/rules/no-duplicate-imports.md

   1 ---
   2 title: no-duplicate-imports
   3 layout: doc
   4 rule_type: problem
   5 ---
   6
   7
   8 Using a single `import` statement per module will make the code clearer because you can see everything being imported from that module on one line.
   9
  10 In the following example the `module` import on line 1 is repeated on line 3. These can be combined to make the list of imports more succinct.
  11
  12 ```js
  13 import { merge } from 'module';
  14 import something from 'another-module';
  15 import { find } from 'module';
  16 ```
  17
  18 ## Rule Details
  19
  20 This rule requires that all imports from a single module that can be merged exist in a single `import` statement.
  21
  22 Example of **incorrect** code for this rule:
  23
  24 ::: incorrect
  25
  26 ```js
  27 /*eslint no-duplicate-imports: "error"*/
  28
  29 import { merge } from 'module';
  30 import something from 'another-module';
  31 import { find } from 'module';
  32 ```
  33
  34 :::
  35
  36 Example of **correct** code for this rule:
  37
  38 ::: correct
  39
  40 ```js
  41 /*eslint no-duplicate-imports: "error"*/
  42
  43 import { merge, find } from 'module';
  44 import something from 'another-module';
  45 ```
  46
  47 :::
  48
  49 Example of **correct** code for this rule:
  50
  51 ::: correct
  52
  53 ```js
  54 /*eslint no-duplicate-imports: "error"*/
  55
  56 // not mergeable
  57 import { merge } from 'module';
  58 import * as something from 'module';
  59 ```
  60
  61 :::
  62
  63 ## Options
  64
  65 This rule takes one optional argument, an object with a single key, `includeExports` which is a `boolean`. It defaults to `false`.
  66
  67 If re-exporting from an imported module, you should add the imports to the `import`-statement, and export that directly, not use `export ... from`.
  68
  69 Example of **incorrect** code for this rule with the `{ "includeExports": true }` option:
  70
  71 ::: incorrect
  72
  73 ```js
  74 /*eslint no-duplicate-imports: ["error", { "includeExports": true }]*/
  75
  76 import { merge } from 'module';
  77
  78 export { find } from 'module';
  79 ```
  80
  81 :::
  82
  83 Example of **correct** code for this rule with the `{ "includeExports": true }` option:
  84
  85 ::: correct
  86
  87 ```js
  88 /*eslint no-duplicate-imports: ["error", { "includeExports": true }]*/
  89
  90 import { merge, find } from 'module';
  91
  92 export { find };
  93 ```
  94
  95 :::
  96
  97 Example of **correct** code for this rule with the `{ "includeExports": true }` option:
  98
  99 ::: correct
 100
 101 ```js
 102 /*eslint no-duplicate-imports: ["error", { "includeExports": true }]*/
 103
 104 import { merge, find } from 'module';
 105
 106 // cannot be merged with the above import
 107 export * as something from 'module';
 108
 109 // cannot be written differently
 110 export * from 'module';
 111 ```
 112
 113 :::