This plugin intends to support linting of ES2015+ (ES6+) import/export syntax, and prevent issues with misspelling of file paths and import names. All the goodness that the ES2015+ static module syntax intends to provide, marked up in your editor.
IF YOU ARE USING THIS WITH SUBLIME: see the bottom section for important info.
Static analysis:
- Ensure imports point to a file/module that can be resolved. (
no-unresolved
) - Ensure named imports correspond to a named export in the remote file. (
named
) - Ensure a default export is present, given a default import. (
default
) - Ensure imported namespaces contain dereferenced properties as they are dereferenced. (
namespace
)
Helpful warnings:
- Report any invalid exports, i.e. re-export of the same name (
export
) - Report use of exported name as identifier of default export (
no-named-as-default
) - Report use of exported name as property of default export (
no-named-as-default-member
) - Report imported names marked with
@deprecated
documentation tag (no-deprecated
) - Forbid the use of extraneous packages (
no-extraneous-dependencies
)
Module systems:
- Report CommonJS
require
calls andmodule.exports
orexports.*
. (no-commonjs
) - Report AMD
require
anddefine
calls. (no-amd
)
Style guide:
- Ensure all imports appear before other statements (
imports-first
) - Report repeated import of the same module in multiple places (
no-duplicates
) - Report namespace imports (
no-namespace
)
npm install eslint-plugin-import -g
or if you manage ESLint as a dev dependency:
# inside your project's working tree
npm install eslint-plugin-import --save-dev
All rules are off by default. However, you may configure them manually
in your .eslintrc.(yml|json|js)
, or extend one of the canned configs:
---
extends:
- eslint:recommended
- plugin:import/errors
- plugin:import/warnings
# or configure manually:
plugins:
- import
rules:
import/no-unresolved: [2, {commonjs: true, amd: true}]
import/named: 2
import/namespace: 2
import/default: 2
import/export: 2
# etc...
With the advent of module bundlers and the current state of modules and module
syntax specs, it's not always obvious where import x from 'module'
should look
to find the file behind module
.
Up through v0.10ish, this plugin has directly used substack's resolve
plugin,
which implements Node's import behavior. This works pretty well in most cases.
However, Webpack allows a number of things in import module source strings that
Node does not, such as loaders (import 'file!./whatever'
) and a number of
aliasing schemes, such as externals
: mapping a module id to a global name at
runtime (allowing some modules to be included more traditionally via script tags).
In the interest of supporting both of these, v0.11 introduces resolvers.
Currently Node and Webpack resolution have been implemented, but the resolvers are just npm packages, so third party packages are supported (and encouraged!).
Just install a resolver as eslint-import-resolver-foo
and reference it as such:
settings:
import/resolver: foo
or with a config object:
settings:
import/resolver:
foo: { someConfigKey: value }
If you are interesting in writing a resolver, see the spec for more details.
You may set the following settings in your .eslintrc
:
A list of regex strings that, if matched by a path, will
not report the matching module if no export
s are found.
In practice, this means rules other than no-unresolved
will not report on any
import
s with (absolute) paths matching this pattern, unless export
s were
found when parsing. This allows you to ignore node_modules
but still properly
lint packages that define a jsnext:main
in package.json
(Redux, D3's v4 packages, etc.).
no-unresolved
has its own ignore
setting.
Note: setting this explicitly will replace the default of node_modules
, so you
may need to include it in your own list if you still want to ignore it. Example:
settings:
import/ignore:
- node_modules # mostly CommonJS (ignored by default)
- \.coffee$ # fraught with parse errors
- \.(scss|less|css)$ # can't parse unprocessed CSS modules, either
See resolvers.
Settings for cache behavior. Memoization is used at various levels to avoid the copious amount of fs.statSync
/module parse calls required to correctly report errors.
For normal eslint
console runs, the cache lifetime is irrelevant, as we can strongly assume that files should not be changing during the lifetime of the linter process (and thus, the cache in memory)
For long-lasting processes, like eslint_d
or eslint-loader
, however, it's important that there be some notion of staleness.
If you never use eslint_d
or eslint-loader
, you may set the cache lifetime to Infinity
and everything should be fine:
# .eslintrc.yml
settings:
import/cache:
lifetime: ∞ # or Infinity
Otherwise, set some integer, and cache entries will be evicted after that many seconds have elapsed:
# .eslintrc.yml
settings:
import/cache:
lifetime: 5 # 30 is the default
SublimeLinter-eslint introduced a change to support .eslintignore
files
which altered the way file paths are passed to ESLint when linting during editing.
This change sends a relative path instead of the absolute path to the file (as ESLint
normally provides), which can make it impossible for this plugin to resolve dependencies
on the filesystem.
This workaround should no longer be necessary with the release of ESLint 2.0, when
.eslintignore
will be updated to work more like a .gitignore
, which should
support proper ignoring of absolute paths via --stdin-filename
.
In the meantime, see roadhump/SublimeLinter-eslint#58
for more details and discussion, but essentially, you may find you need to add the following
SublimeLinter
config to your Sublime project file:
{
"folders":
[
{
"path": "code"
}
],
"SublimeLinter":
{
"linters":
{
"eslint":
{
"chdir": "${project}/code"
}
}
}
}
Note that ${project}/code
matches the code
provided at folders[0].path
.
The purpose of the chdir
setting, in this case, is to set the working directory
from which ESLint is executed to be the same as the directory on which SublimeLinter-eslint
bases the relative path it provides.
See the SublimeLinter docs on chdir
for more information, in case this does not work with your project.
If you are not using .eslintignore
, or don't have a Sublime project file, you can also
do the following via a .sublimelinterrc
file in some ancestor directory of your
code:
{
"linters": {
"eslint": {
"args": ["--stdin-filename", "@"]
}
}
}
I also found that I needed to set rc_search_limit
to null
, which removes the file
hierarchy search limit when looking up the directory tree for .sublimelinterrc
:
In Package Settings / SublimeLinter / User Settings:
{
"user": {
"rc_search_limit": null
}
}
I believe this defaults to 3
, so you may not need to alter it depending on your
project folder max depth.