A library is a script project whose functions can be reused in other scripts.
Gain access to a library
New editor
To include a library in your project you must have at least view-level access to it. If you aren't the author of the library that you want to include, contact the author and request access.
You need the script ID of the library you want to include. When you have access to the library, you can find the script ID on the Project Settings
page.Legacy editor
To include a library in your project you must have at least read-level access to it. If you are not the author of the library that you want to include, you need to contact the author and request them to grant you access.
You also need the project key of the library you are including. If you have access to the library, you can find the project key under File > Project Properties... Otherwise, you need to ask the author of the library to give you the project key.
Add a library to your script project
New editor
- At the left of the Apps Script editor, next to "Libraries," click Add a library .
- In the "Script ID" field, paste in the script ID of the library.
- Click Look up.
- Click the Version dropdown and select the version of the library to use.
- Check to see if the default "Identifier" name is the one that you want to
use with this library. This is the name that your script uses to
refer to the library. For example, if you set it to
Test
then you can call a method of that library as follows:Test.libraryMethod()
. - Click Add.
Legacy editor
- Select Resources > Libraries...
- Paste in the project key of the library that you want to use into the Add a Library text box.
- Click Add to add the library to your project.
- Click on the Version dropdown and select a version of this library that
you want to use.
- Check to see if the default Identifier name is the one that you would
like to use with this library. This is the name that your script uses to
refer to the library. For example, if you set it to
Test
then you could call a method of that library as follows:Test.libraryMethod()
. - Enable Development mode if you want to override the selected version. For more information, see Testing and debugging a library.
- Click Save to save the libraries you have added and close the dialog box.
Use a library
Use your included library as you would use a default service. For
example, if Test
is the identifier for your library, type
Test
immediately followed by a period to see the list of methods in the library.
The reference documentation for an included library can be opened by following these steps:
New editor
At the left of the script editor, next to the library name, click More
> Open in a new tab.Legacy editor
- Select Resources > Libraries
- The name of the library that you have included is a link that opens a new browser tab which contains the reference documentation for this library.
Remove a library
New editor
At the left of the script editor, next to the library name, click More
> Remove > Remove library.Legacy editor
- Select Resources > Libraries.
- Click on the X button to the right of the library to delete it.
- Click Save for the changes to take effect.
Update a library
You can change the version of the library or update its identifier.
New editor
- At the left of the editor, under "Libraries," click the name of the library.
- Make your changes and click Save.
Legacy editor
- At the top of the editor, click Resources > Libraries.
- Make your changes and click Save.
Create and share a library
To use and share your script project as a library, follow the below steps.
New editor
- Create a versioned deployment of your script.
- Share at least view-level access with all potential users of the library.
- Give those users the script ID, which can be found on the Project settings page.
Legacy editor
- Save a version of the script project.
- Grant at least read-level access to all potential users of the library.
- Give those users the library's project key, which can be found under File > Project Properties.
Best practices
Here are some guidelines to follow when writing a library:
- Choose a meaningful name for your project since it's used as the default identifier when your library is included by others.
- If you want one or more methods of your script to not be visible (nor
usable) to your library users, you can end the name of the method with an
underscore. For example,
myPrivateMethod_()
. - Only enumerable global properties are visible to library users. This includes function
declarations, variables created outside a function with
var
, and properties explicitly set on the global object. For example,Object.defineProperty()
withenumerable
set tofalse
creates a symbol you can use in your library, but this symbol isn't accessible by your users. If you want your library users to make use of the script editor autocomplete and the automatically generated documentation, you must have JSDoc-style documentation for all your functions. Here's an example:
/** * Raises a number to the given power, and returns the result. * * @param {number} base the number we're raising to a power * @param {number} exp the exponent we're raising the base to * @return {number} the result of the exponential calculation */ function power(base, exp) { ... }
Resource scoping
There are two types of resources when you are working with libraries: shared and not-shared. A shared resource means that both the library and the including script have a built-in access to the same instance of the resource. The following diagram illustrates a shared resource using the example of User Properties:
A not-shared resource means that both library and the including script have built-in access only to their instance of the resource. However, a library can provide access to its not-shared resources by having explicit functions that operate on them. Here is an example of a function that you would include in your library to expose its Script Properties:
function getLibraryProperty(key) {
return ScriptProperties.getProperty(key);
}
The following diagram illustrates a not-shared resource using the example of Script Properties:
This table lists the shared and not-shared resources for your reference:
Resource | Shared* | Not-Shared** | Notes |
---|---|---|---|
Lock | The same instance is visible to all including scripts when created in the library. | ||
Script Properties | The same instance is visible to all including scripts when created in the library. | ||
Cache | The same instance is visible to all including scripts when created in the library. | ||
Triggers | Simple triggers created in library are not triggered by the including script. | ||
ScriptApp | |||
UiApp |
|
||
User Properties | |||
Logger and execution transcript | |||
Sites, Spreadsheets and other containers | A call to getActive() returns the container of the
including script. |
||
MailApp and GmailApp | |||
* This means that the library does not have its own instance of the
feature/resource and instead is using the one created by the script
that invoked it.
** This means that library has its own instance of the resource/feature and that all scripts that use the library share and have access to that same instance. |
Test a library
New editor
To test your library, use the head deployment. Anyone who has editor-level access to the script can use the head deployment.
Legacy editor
When you are writing a library and doing a lot of testing, you should use Development mode. Once the development mode is on, the following becomes true:
- Anyone who has editor-level access to the script has the latest changes made to the files in the library project even if it was not saved as a version.
- Anyone with only the read-level access to the script still uses the selected version regardless of whether the development mode is on or off.
Debug a library
When you use the debugger in a project that includes a library you can step into a function of the included library. The code shows up in the debugger in view-only mode and at the right version.