mirror of
https://github.com/denoland/deno.git
synced 2024-12-25 00:29:09 -05:00
76 lines
2.3 KiB
Markdown
76 lines
2.3 KiB
Markdown
## Location API
|
|
|
|
Deno supports the
|
|
[`location`](https://developer.mozilla.org/en-US/docs/Web/API/Window/location)
|
|
global from the web. Please read on.
|
|
|
|
### Location flag
|
|
|
|
There is no "web page" whose URL we can use for a location in a Deno process. We
|
|
instead allow users to emulate a document location by specifying one on the CLI
|
|
using the `--location` flag. It can be a `http` or `https` URL.
|
|
|
|
```ts
|
|
// deno run --location https://example.com/path main.ts
|
|
|
|
console.log(location.href);
|
|
// "https://example.com/path"
|
|
```
|
|
|
|
You must pass `--location <href>` for this to work. If you don't, any access to
|
|
the `location` global will throw an error.
|
|
|
|
```ts
|
|
// deno run main.ts
|
|
|
|
console.log(location.href);
|
|
// error: Uncaught ReferenceError: Access to "location", run again with --location <href>.
|
|
```
|
|
|
|
Setting `location` or any of its fields will normally cause navigation in
|
|
browsers. This is not applicable in Deno, so it will throw in this situation.
|
|
|
|
```ts
|
|
// deno run --location https://example.com/path main.ts
|
|
|
|
location.pathname = "./foo";
|
|
// error: Uncaught NotSupportedError: Cannot set "location.pathname".
|
|
```
|
|
|
|
### Extended usage
|
|
|
|
On the web, resource resolution (excluding modules) typically uses the value of
|
|
`location.href` as the root on which to base any relative URLs. This affects
|
|
some web APIs adopted by Deno.
|
|
|
|
#### Fetch API
|
|
|
|
```ts
|
|
// deno run --location https://api.github.com/ --allow-net main.ts
|
|
|
|
const response = await fetch("./orgs/denoland");
|
|
// Fetches "https://api.github.com/orgs/denoland".
|
|
```
|
|
|
|
The `fetch()` call above would throw if the `--location` flag was not passed,
|
|
since there is no web-analogous location to base it onto.
|
|
|
|
#### Worker modules
|
|
|
|
```ts
|
|
// deno run --location https://example.com/index.html --allow-net main.ts
|
|
|
|
const worker = new Worker("./workers/hello.ts", { type: "module" });
|
|
// Fetches worker module at "https://example.com/workers/hello.ts".
|
|
```
|
|
|
|
### Only use if necessary
|
|
|
|
For the above use cases, it is preferable to pass URLs in full rather than
|
|
relying on `--location`. You can manually base a relative URL using the `URL`
|
|
constructor if needed.
|
|
|
|
The `--location` flag is intended for those who have some specific purpose in
|
|
mind for emulating a document location and are aware that this will only work at
|
|
application-level. However, you may also use it to silence errors from a
|
|
dependency which is frivolously accessing the `location` global.
|