1 ---
2 title: npm-dedupe
3 section: 1
4 description: Reduce duplication in the package tree
5 github_repo: npm/cli
6 github_branch: release/v9
7 github_path: docs/lib/content/commands/npm-dedupe.md
8 redirect_from:
9 - /cli-documentation/v9/cli-commands/dedupe
10 - /cli-documentation/v9/cli-commands/npm-dedupe
11 - /cli-documentation/v9/commands/dedupe
12 - /cli-documentation/v9/commands/npm-dedupe
13 - /cli-documentation/v9/dedupe
14 - /cli-documentation/v9/npm-dedupe
15 - /cli/v9/cli-commands/dedupe
16 - /cli/v9/cli-commands/npm-dedupe
17 - /cli/v9/commands/dedupe
18 - /cli/v9/dedupe
19 - /cli/v9/npm-dedupe
20 ---
21
22 ### Synopsis
23
24 ```bash
25 npm dedupe
26
27 alias: ddp
28 ```
29
30 ### Description
31
32 Searches the local package tree and attempts to simplify the overall structure by moving dependencies further up the tree, where they can be more effectively shared by multiple dependent packages.
33
34 For example, consider this dependency graph:
35
36 ```
37 a
38 +-- b <-- depends on c@1.0.x
39 | `-- c@1.0.3
40 `-- d <-- depends on c@~1.0.9
41 `-- c@1.0.10
42 ```
43
44 In this case, `npm dedupe` will transform the tree to:
45
46 ```bash
47 a
48 +-- b
49 +-- d
50 `-- c@1.0.10
51 ```
52
53 Because of the hierarchical nature of node's module lookup, b and d will both get their dependency met by the single c package at the root level of the tree.
54
55 In some cases, you may have a dependency graph like this:
56
57 ```
58 a
59 +-- b <-- depends on c@1.0.x
60 +-- c@1.0.3
61 `-- d <-- depends on c@1.x
62 `-- c@1.9.9
63 ```
64
65 During the installation process, the `c@1.0.3` dependency for `b` was placed in the root of the tree. Though `d`'s dependency on `c@1.x` could have been satisfied by `c@1.0.3`, the newer `c@1.9.0` dependency was used, because npm favors updates by default, even when doing so causes duplication.
66
67 Running `npm dedupe` will cause npm to note the duplication and re-evaluate, deleting the nested `c` module, because the one in the root is sufficient.
68
69 To prefer deduplication over novelty during the installation process, run `npm install --prefer-dedupe` or `npm config set prefer-dedupe true`.
70
71 Arguments are ignored. Dedupe always acts on the entire tree.
72
73 Note that this operation transforms the dependency tree, but will never result in new modules being installed.
74
75 Using `npm find-dupes` will run the command in `--dry-run` mode.
76
77 Note: `npm dedupe` will never update the semver values of direct dependencies in your project `package.json`, if you want to update values in `package.json` you can run: `npm update --save` instead.
78
79 ### Configuration
80
81 #### `install-strategy`
82
83 - Default: "hoisted"
84 - Type: "hoisted", "nested", "shallow", or "linked"
85
86 Sets the strategy for installing packages in node_modules. hoisted (default): Install non-duplicated in top-level, and duplicated as necessary within directory structure. nested: (formerly --legacy-bundling) install in place, no hoisting. shallow (formerly --global-style) only install direct deps at top-level. linked: (experimental) install in node_modules/.store, link in place, unhoisted.
87
88 #### `legacy-bundling`
89
90 - Default: false
91 - Type: Boolean
92 - DEPRECATED: This option has been deprecated in favor of `--install-strategy=nested`
93
94 Instead of hoisting package installs in `node_modules`, install packages in the same manner that they are depended on. This may cause very deep directory structures and duplicate package installs as there is no de-duplicating. Sets `--install-strategy=nested`.
95
96 #### `global-style`
97
98 - Default: false
99 - Type: Boolean
100 - DEPRECATED: This option has been deprecated in favor of `--install-strategy=shallow`
101
102 Only install direct dependencies in the top level `node_modules`, but hoist on deeper dependencies. Sets `--install-strategy=shallow`.
103
104 #### `strict-peer-deps`
105
106 - Default: false
107 - Type: Boolean
108
109 If set to `true`, and `--legacy-peer-deps` is not set, then _any_ conflicting `peerDependencies` will be treated as an install failure, even if npm could reasonably guess the appropriate resolution based on non-peer dependency relationships.
110
111 By default, conflicting `peerDependencies` deep in the dependency graph will be resolved using the nearest non-peer dependency specification, even if doing so will result in some packages receiving a peer dependency outside the range set in their package's `peerDependencies` object.
112
113 When such an override is performed, a warning is printed, explaining the conflict and the packages involved. If `--strict-peer-deps` is set, then this warning is treated as a failure.
114
115 #### `package-lock`
116
117 - Default: true
118 - Type: Boolean
119
120 If set to false, then ignore `package-lock.json` files when installing. This will also prevent _writing_ `package-lock.json` if `save` is true.
121
122 #### `omit`
123
124 - Default: 'dev' if the `NODE_ENV` environment variable is set to 'production', otherwise empty.
125 - Type: "dev", "optional", or "peer" (can be set multiple times)
126
127 Dependency types to omit from the installation tree on disk.
128
129 Note that these dependencies _are_ still resolved and added to the `package-lock.json` or `npm-shrinkwrap.json` file. They are just not physically installed on disk.
130
131 If a package type appears in both the `--include` and `--omit` lists, then it will be included.
132
133 If the resulting omit list includes `'dev'`, then the `NODE_ENV` environment variable will be set to `'production'` for all lifecycle scripts.
134
135 #### `ignore-scripts`
136
137 - Default: false
138 - Type: Boolean
139
140 If true, npm does not run scripts specified in package.json files.
141
142 Note that commands explicitly intended to run a particular script, such as `npm start`, `npm stop`, `npm restart`, `npm test`, and `npm run-script` will still run their intended script if `ignore-scripts` is set, but they will _not_ run any pre- or post-scripts.
143
144 #### `audit`
145
146 - Default: true
147 - Type: Boolean
148
149 When "true" submit audit reports alongside the current npm command to the default registry and all registries configured for scopes. See the documentation for [`npm audit`](/cli/v9/commands/npm-audit) for details on what is submitted.
150
151 #### `bin-links`
152
153 - Default: true
154 - Type: Boolean
155
156 Tells npm to create symlinks (or `.cmd` shims on Windows) for package executables.
157
158 Set to false to have it not do this. This can be used to work around the fact that some file systems don't support symlinks, even on ostensibly Unix systems.
159
160 #### `fund`
161
162 - Default: true
163 - Type: Boolean
164
165 When "true" displays the message at the end of each `npm install` acknowledging the number of dependencies looking for funding. See [`npm fund`](/cli/v9/commands/npm-fund) for details.
166
167 #### `dry-run`
168
169 - Default: false
170 - Type: Boolean
171
172 Indicates that you don't want npm to make any changes and that it should only report what it would have done. This can be passed into any of the commands that modify your local installation, eg, `install`, `update`, `dedupe`, `uninstall`, as well as `pack` and `publish`.
173
174 Note: This is NOT honored by other network related commands, eg `dist-tags`, `owner`, etc.
175
176 #### `workspace`
177
178 - Default:
179 - Type: String (can be set multiple times)
180
181 Enable running a command in the context of the configured workspaces of the current project while filtering by running only the workspaces defined by this configuration option.
182
183 Valid values for the `workspace` config are either:
184
185 - Workspace names
186 - Path to a workspace directory
187 - Path to a parent workspace directory (will result in selecting all workspaces within that folder)
188
189 When set for the `npm init` command, this may be set to the folder of a workspace which does not yet exist, to create the folder and set it up as a brand new workspace within the project.
190
191 This value is not exported to the environment for child processes.
192
193 #### `workspaces`
194
195 - Default: null
196 - Type: null or Boolean
197
198 Set to true to run the command in the context of **all** configured workspaces.
199
200 Explicitly setting this to false will cause commands like `install` to ignore workspaces altogether. When not set explicitly:
201
202 - Commands that operate on the `node_modules` tree (install, update, etc.) will link workspaces into the `node_modules` folder. - Commands that do other things (test, exec, publish, etc.) will operate on the root project, _unless_ one or more workspaces are specified in the `workspace` config.
203
204 This value is not exported to the environment for child processes.
205
206 #### `include-workspace-root`
207
208 - Default: false
209 - Type: Boolean
210
211 Include the workspace root when workspaces are enabled for a command.
212
213 When false, specifying individual workspaces via the `workspace` config, or all workspaces via the `workspaces` flag, will cause npm to operate only on the specified workspaces, and not on the root project.
214
215 This value is not exported to the environment for child processes.
216
217 #### `install-links`
218
219 - Default: false
220 - Type: Boolean
221
222 When set file: protocol dependencies will be packed and installed as regular dependencies instead of creating a symlink. This option has no effect on workspaces.
223
224 ### See Also
225
226 - [npm find-dupes](/cli/v9/commands/npm-find-dupes)
227 - [npm ls](/cli/v9/commands/npm-ls)
228 - [npm update](/cli/v9/commands/npm-update)
229 - [npm install](/cli/v9/commands/npm-install)