Specifying dependencies and devDependencies in a package.json file

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To specify the packages your project depends on, you must list them as"dependencies" or"devDependencies" in your package'spackage.json file. When you (or another user) runnpm install, npm will download dependencies and devDependencies that are listed inpackage.json that meet thesemantic version requirements listed for each. To see which versions of a package will be installed, use thesemver calculator.

"dependencies": Packages required by your application in production.
"devDependencies": Packages that are only needed for local development and testing.

Adding dependencies to a`package.json` file

You can add dependencies to apackage.json file from the command line or by manually editing thepackage.json file.

Adding dependencies to a`package.json` file from the command line

To add dependencies and devDependencies to apackage.json file from the command line, you can install them in the root directory of your package using the--save-prod flag (also-S) for dependencies (the default behavior ofnpm install) or the--save-dev flag (also-D) for devDependencies.

To add an entry to the"dependencies" attribute of apackage.json file, on the command line, run the following command:

npm install <package-name> [--save-prod]

To add an entry to the"devDependencies" attribute of apackage.json file, on the command line, run the following command:

npm install <package-name> --save-dev

Manually editing the`package.json` file

To add dependencies to apackage.json file, in a text editor, add an attribute called"dependencies" that references the name andsemantic version of each dependency:

{
"name":"my_package",
"version":"1.0.0",
"dependencies":{
"my_dep":"^1.0.0",
"another_dep":"~2.2.0"
}
}

To add devDependencies to apackage.json file, in a text editor, add an attribute called"devDependencies" that references the name andsemantic version of each devDependency:

"name":"my_package",
"version":"1.0.0",
"dependencies":{
"my_dep":"^1.0.0",
"another_dep":"~2.2.0"
},
"devDependencies":{
"my_test_framework":"^3.1.0",
"another_dev_dep":"1.0.0 - 1.2.0"
}