LanguageDetector: measureInputUsage() method

{{APIRef("Translator and Language Detector APIs")}}{{SeeCompatTable}}{{securecontext_header}}

The measureInputUsage() method of the {{domxref("LanguageDetector")}} interface reports how much input quota would be used by a language detection 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_inline}}
  • : An object specifying configuration options for the measureInputUsage() operation. Possible values include:
    • signal
      • : An {{domxref("AbortSignal")}} object instance, which allows the measureInputUsage() operation to be aborted via the associated {{domxref("AbortController")}}.

Return value

A {{jsxref("Promise")}} that fulfills with a number specifying the {{domxref("LanguageDetector.inputQuota", "inputQuota")}} usage of the given input text.

This number is implementation-dependant; if it is less than the {{domxref("LanguageDetector.inputQuota", "inputQuota")}}, the string's language can be detected.

Exceptions

• NotAllowedError {{domxref("DOMException")}}
  • : Thrown if usage of the LanguageDetector API is blocked by a {{httpheader('Permissions-Policy/language-detector','language-detector')}} {{httpheader("Permissions-Policy")}}.
• UnknownError {{domxref("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 enough quota

In the below snippet, we create a new LanguageDetector instance using {{domxref("LanguageDetector.create_static", "create()")}}, then return the total input quota via {{domxref("LanguageDetector.inputQuota", "inputQuota")}} and the input quota usage for a detecting a particular text string's language via measureInputUsage().

We then test to see if the individual input usage for that string is greater than the total available quota. If so, we throw an appropriate error; it not, we commence detecting the string's language using {{domxref("LanguageDetector.detect", "detect()")}}.

const detector = await LanguageDetector.create({
  expectedInputLanguages: ["en-US", "zh"],
});

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

if (inputUsage > totalInputQuota) {
  throw new Error("Insufficient quota to detect languages.");
} else {
  console.log("Quota available to detect languages.");
  const results = await detector.detect(myTextString);
  // ...
}

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• Using the Translator and Language Detector APIs