The import.meta
object exposes context-specific metadata to a JavaScript module. It contains information about the module, like the module's URL.
import.meta
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 |
---|
ECMAScript Language Specification # prod-ImportMeta |
HTML Standard # hostgetimportmetaproperties |
Browser compatibility
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | Deno | Node.js | |
import.meta |
64
|
79
|
62
|
No
|
51
|
11.1
|
64
|
64
|
62
|
47
|
12
|
9.0
|
1.0
|
10.4.0
|
See also
© 2005–2022 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import.meta