The import.meta
object exposes context-specific metadata to a JavaScript module. It contains information about the module, like the module's URL.
Syntax
import.meta
Description
The syntax consists of the keyword import
, a dot, and the identifier meta
. Normally the left-hand side of the dot is the object on which property access is performed, but here import
is not really an object.
The import.meta
object is created by the ECMAScript implementation, with a null
prototype. The object is extensible, and its properties are writable, configurable, and enumerable.
Examples
Using import.meta
Given a module my-module.js
<script type="module" src="my-module.js"></script>
you can access meta information about the module using the import.meta
object.
console.log(import.meta); // { url: "file:///home/user/my-module.js" }
It returns an object with a url
property indicating the base URL of the module. This will either be the URL from which the script was obtained, for external scripts, or the document base URL of the containing document, for inline scripts.
Note that this will include query parameters and/or hash (i.e., following the ?
or #
).
For example, with the following HTML:
<script type="module"> import './index.mjs?someURLInfo=5'; </script>
..the following JavaScript file will log the `someURLInfo
parameter:
// index.mjs new URL(import.meta.url).searchParams.get('someURLInfo'); // 5
The same applies when a file imports another:
// index.mjs import './index2.mjs?someURLInfo=5'; // index2.mjs new URL(import.meta.url).searchParams.get('someURLInfo'); // 5
Note that while Node.js will pass on query parameters (or the hash) as in the latter example, as of Node 14.1.0, a URL with query parameters will err when loading in the form node --experimental-modules index.mjs?someURLInfo=5
(it is treated as a file rather than a URL in this context).
Such file-specific argument passing may be complementary to that used in the application-wide location.href
(with query strings or hash added after the HTML file path) (or on Node.js, through process.argv
).
Specifications
Specification |
---|
import.meta proposal |
HTML Living Standard The definition of 'import.meta' in that specification. |
Browser compatibility
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
import.meta | Chrome Full support 64 | Edge Full support 79 | Firefox Full support 62 | IE No support No | Opera Full support 51 | Safari Full support 11.1 | WebView Android Full support 64 | Chrome Android Full support 64 | Firefox Android Full support 62 | Opera Android Full support 47 | Safari iOS Full support 12 | Samsung Internet Android Full support 9.0 | nodejs Full support 10.4.0 |
Legend
- Full support
- Full support
- No support
- No support
Implementation Progress
The following table provides a daily implementation status for this feature, because this feature has not yet reached cross-browser stability. The data is generated by running the relevant feature tests in Test262, the standard test suite of JavaScript, in the nightly build, or latest release of each browser's JavaScript engine.