Summarizer: measureInputUsage() method

The measureInputUsage() method of the Summarizer interface reports how much inputQuota would be used by a summarize operation for a given text input.

Syntax

measureInputUsage(input)
measureInputUsage(input, options)

Parameters

input

A string representing the input text you want an input usage measurement for.

options Optional

An object specifying configuration options for the measureInputUsage() operation. Possible values include:

context

A string describing the context the input text would be used in, to help generate a more suitable summary.

signal

An AbortSignal object instance, which allows the measureInputUsage() operation to be aborted via the associated AbortController.

Return value

A Promise that fulfills with a number specifying the inputQuota usage of the given input text.

Exceptions

NotAllowedError DOMException

Thrown if usage of the Summarizer API is blocked by a summarizer Permissions-Policy.

NotReadableError DOMException

Thrown if the output summary was filtered by the user agent, for example because it was detected to be harmful, inaccurate, or nonsensical.

NotSupportedError DOMException

Thrown if the provided context is not in language the Summarizer supports.

UnknownError DOMException

Thrown if the measureInputUsage() call failed for any other reason, or a reason the user agent did not wish to disclose.

Examples

Checking if you have sufficient quota

In the below snippet, we create a new Summarizer instance using create(), then return the total input quota via inputQuota and the input quota usage for a summarizing a particular text string via measureInputUsage().

We then test to see if the individual input usage for that string is great than the total available quota. If so, we throw an appropriate error; it not, we commence summarizing the string using summarize().

const summarizer = await Summarizer.create({
  sharedContext:
    "A general summary to help a user decide if the text is worth reading",
  type: "tldr",
  length: "short",
});

const totalInputQuota = summarizer.inputQuota;
const inputUsage = await summarizer.measureInputUsage(myTextString);

if (inputUsage > totalInputQuota) {
  throw new Error("Boo, insufficient quota to generate a summary.");
} else {
  console.log("Yay, quota available to generate a summary.");
  const summary = await summarizer.summarize(myTextString);
  // ...
}

Specifications

Browser compatibility

See also

• Using the Summarizer API
• Web AI demos on chrome.dev