chrome.types

Description

The chrome.types API contains type declarations for Chrome.

Chrome settings

The ChromeSetting type provides a common set of functions (get(), set(), and clear()) as well as an event publisher (onChange) for settings of the Chrome browser. The proxy settings examples demonstrate how these functions are intended to be used.

Scope and lifecycle

Chrome distinguishes between three different scopes of browser settings:

regular
Settings set in the regular scope apply to regular browser windows and are inherited by incognito windows if they are not overwritten. These settings are stored to disk and remain in place until they are cleared by the governing extension, or the governing extension is disabled or uninstalled.
incognito_persistent
Settings set in the incognito_persistent scope apply only to incognito windows. For these, they override regular settings. These settings are stored to disk and remain in place until they are cleared by the governing extension, or the governing extension is disabled or uninstalled.
incognito_session_only
Settings set in the incognito_session_only scope apply only to incognito windows. For these, they override regular and incognito_persistent settings. These settings are not stored to disk and are cleared when the last incognito window is closed. They can only be set when at least one incognito window is open.

Precedence

Chrome manages settings on different layers. The following list describes the layers that may influence the effective settings, in increasing order of precedence.

  1. System settings provided by the operating system
  2. Command-line parameters
  3. Settings provided by extensions
  4. Policies

As the list implies, policies might overrule any changes that you specify with your extension. You can use the get() function to determine whether your extension is capable of providing a setting or whether this setting would be overridden.

As discussed previously, Chrome allows using different settings for regular windows and incognito windows. The following example illustrates the behavior. Assume that no policy overrides the settings and that an extension can set settings for regular windows (R) and settings for incognito windows (I).

  • If only (R) is set, these settings are effective for both regular and incognito windows.
  • If only (I) is set, these settings are effective for only incognito windows. Regular windows use the settings determined by the lower layers (command-line options and system settings).
  • If both (R) and (I) are set, the respective settings are used for regular and incognito windows.

If two or more extensions want to set the same setting to different values, the extension installed most recently takes precedence over the other extensions. If the most recently installed extension sets only (I), the settings of regular windows can be defined by previously installed extensions.

The effective value of a setting is the one that results from considering the precedence rules. It is used by Chrome.

Types

ChromeSetting

An interface that allows access to a Chrome browser setting. See accessibilityFeatures for an example.

Properties

  • onChange

    Event<functionvoidvoid>

    Fired after the setting changes.

    The onChange.addListener function looks like: 

    (callback: function) => {...}

    • callback

      function

      The callback parameter looks like: 

      (details: object) => void

      • details

        object

        • incognitoSpecific

          boolean optional

          Whether the value that has changed is specific to the incognito session. This property will only be present if the user has enabled the extension in incognito mode.

        • levelOfControl

          LevelOfControl

          The level of control of the setting.

        • value

          T

          The value of the setting after the change.

  • clear

    void

    Promise

    Clears the setting, restoring any default value.

    The clear function looks like: 

    (details: object, callback?: function) => {...}

    • details

      object

      Which setting to clear.

    • callback

      function optional

      The callback parameter looks like: 

      () => void

    • returns

      Promise<void>

      Chrome 96+

      Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

  • get

    void

    Promise

    Gets the value of a setting.

    The get function looks like: 

    (details: object, callback?: function) => {...}

    • details

      object

      Which setting to consider.

      • incognito

        boolean optional

        Whether to return the value that applies to the incognito session (default false).

    • callback

      function optional

      The callback parameter looks like: 

      (details: object) => void

      • details

        object

        Details of the currently effective value.

        • incognitoSpecific

          boolean optional

          Whether the effective value is specific to the incognito session. This property will only be present if the incognito property in the details parameter of get() was true.

        • levelOfControl

          LevelOfControl

          The level of control of the setting.

        • value

          T

          The value of the setting.

    • returns

      Promise<object>

      Chrome 96+

      Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

  • set

    void

    Promise

    Sets the value of a setting.

    The set function looks like: 

    (details: object, callback?: function) => {...}

    • details

      object

      Which setting to change.

      • scope

        ChromeSettingScope optional

        Where to set the setting (default: regular).

      • value

        T

        The value of the setting. Note that every setting has a specific value type, which is described together with the setting. An extension should not set a value of a different type.

    • callback

      function optional

      The callback parameter looks like: 

      () => void

    • returns

      Promise<void>

      Chrome 96+

      Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

ChromeSettingScope

Chrome 44+

The scope of the ChromeSetting. One of

  • regular: setting for the regular profile (which is inherited by the incognito profile if not overridden elsewhere),
  • regular\_only: setting for the regular profile only (not inherited by the incognito profile),
  • incognito\_persistent: setting for the incognito profile that survives browser restarts (overrides regular preferences),
  • incognito\_session\_only: setting for the incognito profile that can only be set during an incognito session and is deleted when the incognito session ends (overrides regular and incognito_persistent preferences).

Enum

"regular"

"regular_only"

"incognito_persistent"

"incognito_session_only"

LevelOfControl

Chrome 44+

One of

  • not\_controllable: cannot be controlled by any extension
  • controlled\_by\_other\_extensions: controlled by extensions with higher precedence
  • controllable\_by\_this\_extension: can be controlled by this extension
  • controlled\_by\_this\_extension: controlled by this extension

Enum

"not_controllable"

"controlled_by_other_extensions"

"controllable_by_this_extension"

"controlled_by_this_extension"