A lightweight, dead-simple, type-safe reactive query parameter store built for Svelte 5.
npm install svelte-query-paramsThe easiest way to reactively manage query params in Svelte _and_ SvelteKit applications, both on the server and in the browser. Built for Svelte 5 and integrates with existing validation libraries to parse, coerce and transform query params into the data your application needs.
svelte^5 is required:
``bash`
npm install svelte-query-params svelte@next
`bash`
pnpm install svelte-query-params svelte@next
`bash`
yarn add svelte-query-params svelte@next
`bash`
bun install svelte-query-params svelte@next
svelte requires a version of 5.0.0-next.169 or newer as it renamed a public API that this library uses.
By default, svelte-query-params uses URLSearchParams to handle interpreting the location string, which means it does not decode null and has limited handling of other more advanced URL parameter configurations. If you want access to those features, add a third-party library like query-string and tell svelte-query-params to use it.
- Reactivity: The library providies a reactive object that reflects the current state of query parameters.
- Browser and Server Support: The utility is designed to work seamlessly in both browser and server environments.
- Customizable Validators: Define validators for each query parameter to ensure proper data types and constraints.
- Debounced Updates: Optionally debounce updates to query parameters to optimize performance.
- Event Handling: Automatically handles popstate events for accurate synchronisation with browser history.
- Serialisation: Control how query params are serialised into strings to the browser
- Multi-value params: Supports multi-value query parameters with ease
In some lib file e.g., src/lib/params.ts:
`javascript
import { createUseQueryParams } from "svelte-query-params";
// Define validators for query parameters
const validators = {
page: (value) => typeof value === "number" && value > 0,
q: (value) => typeof value === "string",
};
// Create the hook
export const useQueryParams = createUseQueryParams(validators);
`
createUseQueryParams returns a hook, rather than the reactive object itself, as the reactive nature may be lost when exporting and importing these files.
Then you can use this hook in your Svelte components:
`svelte
Currently on page {params.page}, searching for {params.q}
`
svelte-query-params supports zod, valibot and function validators to define the schema for query params. Therefore, you do not need to learn an extra API for validating data.
When using zod or valibot, you do not need to wrap your schemaz.object({ ... })
in zod or valibot object:
`javascript
import { z } from "zod";
import { createUseQueryParams } from "svelte-query-params";
const useQueryParams = createUseQueryParams({
page: z.number(),
q: z.string()
});
`
But you can if you want.
Note that it is possible to mix and match the schemas if needed:
`javascript
import { z } from "zod";
import { string } from "valibot";
import { createUseQueryParams } from "svelte-query-params";
const useQueryParams = createUseQueryParams({
page: (value) => typeof value === "number" && value > 0,
sort: string(),
q: z.string()
});
`
With a function validator, you may receive the param as either a string, an array of strings, or undefined. As a result, you must handle all three cases to support multi-value params:
`javascript`
const validators = {
categories: (value) => {
if (!value) return []
return Array.isArray(value) ? value : [value]
}
}
With Zod, you need to handle the case where there's either 0 or 1 query param value as this library will not infer this as an array beforehand. You must define your array parameter like:
`javascript
import { z } from "zod";
z.object({
categories: z
.union([z.string().array(), z.string()])
.default([])
.transform((c) => (Array.isArray(c) ? c : [c])),
})
`
The union between a string and array of strings handles 1 or more query params; a default is set to the empty array to allow the parameter to be omitted from the URL and it's transformed at the end to convert the single value param into an array.
In the same manner, with Valibot:
`javascript
import * as v from "valibot";
v.object({
categories: v.pipe(
v.optional(v.union([v.array(v.string()), v.string()]), []),
v.transform((c) => (Array.isArray(c) ? c : [c]))
),
});
`
createUseQueryParams takes an options object as the second argument, with the following properties:
| Option | Default | Description |
|-------------|-------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| windowObj | window | (Optional) Provide a custom implementation of window. It must implement: Window.prototype.location, Window.prototype.history, EventTarget.prototype.addEventListener and EventTarget.prototype.removeEventListener. |debounce
| | 0 | (Optional) The delay in milliseconds before updating the browser URL when the reactive object is updated. This is useful in situations where URL updates happen frequently, e.g., on every keystroke. Note that this only affects the browser URL - the reactive object will always update immediately. |serialise
| | JSON.stringify | (Optional) Control how query params are serialized to the URL. Note that this is NOT for encoding values into URI components - it serializes objects into strings, which will then be encoded internally. This is used for serialising complex objects like dates. |adapter
| | browser | (Optional) Provide a custom adapter that controls fetching/updating query params on both the server and in the browser. |
`javascript
import { createUseQueryParams } from "svelte-query-params";
const useQueryParams = createUseQueryParams({ ... }, {
... // Options here
})
`
As mentioned previously, adapters control how the URL is fetched and updated, both on the server and in the browser. As such, any adapter needs to implement the following interface:
- isBrowser: () => boolean - Returns true when are in the browser, and false otherwise.
- server - A property with the following methods:save(search: string) => void
- - Update the server URL. Note that the search string has the ? prefixed.
- browser - A property with the following methods:read() => URL | Location
- - Retrieve the browser URL.save(search: string, hash: string) => void
- - Update the browser URL. Note that the search string has the ? prefixed and the hash string has the # prefixed.
To create your own adapter, you can import the Adapter type from svelte-query-params/adapter for intellisense, or use defineAdapter also exported by svelte-query-params/adapter:
`typescript
import type { Adapter } from 'svelte-query-params/adapter';
import { defineAdapter } from 'svelte-query-params/adapter';
export const myAdapter: Adapter = { ... }
export const myAdapter = defineAdapter({ ... });
`
This is the default adapter when no adapter is specified and can only be used
in the browser i.e., fetching the URL on the browser returns an empty search string and hash and updating the query params on the server is a no-op.
`javascript
import { createUseQueryParams } from "svelte-query-params";
import { browser } from "svelte-query-params/adapters/browser";
const useQueryParams = createUseQueryParams({ ... }, {
adapter: browser({ ... })
})
`
#### Browser Adapter Options
- windowObj: (Optional) Provide a custom implementation of window. It must implement:Window.prototype.location
-
-
-
-
- replace: (Optional) If this is true, any browser query updates will not create a new browser session history item, replacing the previous one instead. If false, a new item will always be added to the history.
For use with SvelteKit, use this adapter, instead of the browser adapter for support for interacting with query params on the server.
`javascript
import { createUseQueryParams } from "svelte-query-params";
import { sveltekit } from "svelte-query-params/adapters/sveltekit";
const useQueryParams = createUseQueryParams({ ... }, {
adapter: sveltekit({ ... })
})
`
#### SvelteKit Adapter Options
- replace: (Optional) If this is true, any browser query updates will not create a new browser session history item, replacing the previous one instead. If false, a new item will always be added to the history.
See Contributing Guide.
Distributed under the MIT License. See LICENSE` for more information.