Develop Reference

Intercept all Form / POST Events

I'd like to intercept all Form Actions / POST events send to the server to do data validation once, instead each time per page in sveltekit.
I figured the best place might be hooks.server, but it only exposes the handle function, not the actions: Actions that is needed for using invalid( ... ) for returning data validation.
Is there a way to return invalid(...) in hooks.server or access actions:, or is there a better way to handle this?

There is nothing particularly special about invalid. It ultimately causes a JSON response of the form:
{
type: 'invalid',
status: number, // HTTP code
data: any, // Object that will be passed to `form` property of page
}
So you can use the handle hook to do validation, e.g.
import type { Handle } from '#sveltejs/kit';
import { json } from '#sveltejs/kit';
export const handle: Handle = async ({ event, resolve }) => {
if (event.request.method == 'POST') {
const errorInfo = await validate(event.request);
if (errorInfo) {
return json({
type: 'invalid',
status: errorInfo.status,
data: errorInfo.data,
}, { status: errorInfo.status });
}
}
return await resolve(event);
}
async function validate(r: Request) {
// `clone()` so the rest of the code that might also
// try to read the request should not be affected
const data = await r.clone().formData();
// Validation logic here
}

How to check object type from request.body in Typescript?

I need to check the object type from the request body and then run approbiate function based on this type, I try do this in this way:
export interface SomeBodyType {
id: string,
name: string,
[etc....]
}
export const someFunction = async (req: Request, res: Response) => {
const { body } = req.body;
if (body instanceof SomeBodyType) {
//run function A
} else {
// run function B
}
}
but it not work, cause my SomeBodyType return me error: only refers to a type, but is being used as a value here.,
so, how can i check the type of the body in this case?
thanks for any help!
//// EDIT:
thanks to #phn answer I create this generic function to check object types:
export const checkObjectType = <T>(body: T): boolean => {
return (body as T) !== undefined;
}
please, take a look and comment if this function is good

As stated in the comments already, types don't exist in runtime.
You need to write a function to validate the content received in the body, one approach is from the TypeScript documentation (see code example).
A more advanced and dynamic approach is to use a validation library to validate your input against a schema or contract, for example ajv
interface SomeBodyType {
id: string,
name: string
}
function isBodyType(body: any): body is SomeBodyType {
return (body as SomeBodyType).id !== undefined &&
(body as SomeBodyType).name !== undefined;
}
export const someFunction = (req: Request, res: Response) => {
const { body } = { body: { id: '', name: '' } };
if (isBodyType(body)) {
// run function A
} else {
// run function B
}
};

Jest typescript check for type

lets say i have the following interface:
export interface CMSData {
id: number;
url: string;
htmlTag: string;
importJSComponent: string;
componentData: ComponentAttribute[];
}
Then i have a method that returns an array of this object type:
public async GetContent(url: string): Promise<CMSData[]>{
const response = await super.get<ICMSContentData[]>(url, {});
try {
if (response?.parsedBody) {
return this.ProcessResponse(response.parsedBody);
} else {
this.handleHTTPError(new Error("Error"));
return [];
}
} catch (e) {
this.handleHTTPError(e);
return [];
}
}
Then i want to test that this is the case so i write the following test:
import {ContentIOService} from "..";
import {CMSData} from "../IOServices/ContentIOService";
require('es6-promise').polyfill();
require('isomorphic-fetch');
test('Get Content', async () => {
const service = ContentIOService.getInstance();
const data = await service.GetContent("https://1c7207fb14fd3b428c70cc406f0c27d9.m.pipedream.net");
console.log(data)
expect(data).toBeInstanceOf(CMSData[]);
});
However here i get the following error:
'CMSData' only refers to a type, but is being used as a value here.
So how can i test that the data i get back is valid and of the right type?

If the type you're looking for is a call, the .toBeInstanceOf(Class) method accepts a parameter which MUST BE a JavaScript class constructor instead of TS type.
You should let TSC check whether you receive the correct type of data at compile time. Code written inside test suites and test cases is executed at runtime, .toBeInstanceOf(Class) is a runtime check, NOT compiler time.
At runtime, you may want to use expect.objectContaining(object) matches any received object that recursively matches the expected properties.

Unable to pass parameters to service hook through find function in featherjs

Featherjs find service unable to pass extra parameters through find function. In below find service passing extra params data to service.
but unable to receive the value at service hook.
Client code :
return this.app.service('userlist').find({
query: { usersIds: { "$in" : [this.user._id]} },
paginate: false,
params:{ name:'sam' }
}).then(response => {
}).catch(error => {
console.log(error);
});
Server code (Service hook ) :
module.exports = function (options = {}) {
return async function dogetUsr (context) {
const { data } = context;
console.log('Client Param data -->',context.params.name);
return context;
};
};
params data not receiving at server -->
params:{ name:'sam' }
Output at server/service hook :
Client Param data -->undefined

For security reasons, only params.query is passed between the client and the server. In general I wouldn't recommend letting the client disable pagination unless you are guaranteed to only get a few (less than 100) records. Otherwise requests with many records can cause major issues on both sides.
If it is still something you need, you can use the disablePagination hook which lets you set the $limit to -1 if you want to disable pagination:
const { disablePagination } = require('feathers-hooks-common');
module.exports = { before: {
find: disablePagination()
} };

Flow Types with Promises (Fetch's)

I created a Fetch function to consume a JSON API and have defined types for the JSON object. I am confused about how to define the return type for the getCurrentJobAPI function since I do a bunch of .then() afterwards. Is the return value the last .then()? In my code, the last .then() is a setState, so what would the type be for that?
getCurrentJobAPI = (): {} => {
const url: string = `dummy_url&job_id=${this.props.currentJob}`;
return fetch(url, {credentials: 'include'})
.then((response) => {
return response.json();
})
.then((json: CurrentJob) => {
console.log(json);
const location = json.inventoryJob.location;
const ref_note = json.inventoryJob.note;
const id = json.inventoryJob.id;
const models = json.inventoryJobDetails.map((j) => {
return Object.assign({}, {
code: j.code,
qty: j.qty
})
});
this.setState({ currentCodes: models, location: location, ref_note: ref_note, id: id})
return json
})
.then((json: CurrentJob) => {
const barcodes = json.inventoryJob.history;
if (barcodes.length > 0) {
this.setState({apiBarcodes: barcodes})
}
this.calculateRows();
this.insertApiBarcodes();
this.setState({ initialLoad: true });
})
};
UPDATE:
Although I understand that I am supposed to define Promise<type> as the return value of getCurrentJobAPI (see Gilad's answer and comments), I am still unsure why I can't write Promise<CurrentJob> if the Fetch resolves as the JSON response.
[I have condensed my .then() statements per loganfsmyth's recommondation.]
Here are the type definitions for CurrentJob:
type Job = {
user_id: number,
status: 'open' | 'closed',
location: 'string',
history: {[number]: string}[],
note: string,
} & CommonCurrentJob;
type JobDetails = {
iaj_id: number,
code: number,
} & CommonCurrentJob;
type CommonCurrentJob = {
id: number,
qty: number,
qty_changed: number,
created_at: string,
updated_at: string
}

So first off, a disclaimer, I am a TypeScript user but I find that this question is actually applicable to both languages and has the same answer.
I created a Fetch function to consume a JSON API and have defined types for the JSON object. I am confused about how to define the return type for the getCurrentJobAPI function since I do a bunch of .then() afterwards. Is the return value the last .then()? In my code, the last .then() is a setState, so what would the type be for that?
TL;DR: Promise<void> (see note). As you suspect, this is in fact the return type of the last top-level .then in the promise chain.
Now lets dig a bit deeper
Here is your example, reworked very slightly to leverage type inference instead of annotating callback parameters that are declared as any by their receivers.
As an aside, these callback parameter annotations amount to unsafe implicit casts, or type assertions as we call them in TypeScript, and they lie about the shape of the code. They look like this
declare function takesFn(fn: (args: any) => any): void;
So I have minimized these since they form a subtle trap
// #flow
import React from 'react';
type CurrentJob = {
inventoryJob: Job,
inventoryJobDetails: JobDetails[]
}
export default class A extends React.Component<{currentJob:JobDetails}, any> {
getCurrentJobAPI: () => Promise<void> = () => {
const url = `dummy_url&job_id=${String(this.props.currentJob)}`;
return fetch(url, {credentials: 'include'})
.then(response => {
return (response : {json(): any}).json();
}) // --> Promise<any>
.then(json => {
const currentJob = (json: CurrentJob); // make the assumption explicit.
console.log(currentJob);
const {location, id, note: ref_note} = currentJob.inventoryJob;
const currentCodes = currentJob.inventoryJobDetails
.map(({code, qty}) => ({
code,
qty
}));
this.setState({currentCodes, location, ref_note, id});
return currentJob;
}) // --> Promise<CurrentJob>
.then(currentJob => {
const apiBarcodes = currentJob.inventoryJob.history;
if (apiBarcodes.length > 0) {
this.setState({apiBarcodes});
}
this.setState({initialLoad: true});
}); // --> Promise<void>
};
}
So I am making assertions about the promises in each then call above but those assertions are all validated by type inference with the exception of the initial type cast on the response value.
As further evidence, if we remove the type declaration from the getCurrentJobAPI property of A, flow will infer that its type is in fact Promise<void>.
Bonus: simplifying with async/await. I've used several ESNext features above to shorten the code and make it a bit more pleasant, but we can leverage a specific feature, async/await to make it easier to understand control flow and types in Promise based code.
Consider this revision.
// #flow
import React from 'react';
type CurrentJob = {
inventoryJob: Job,
inventoryJobDetails: JobDetails[]
}
export default class A extends React.Component<{currentJob:JobDetails}, any> {
getCurrentJobAPI = async () => {
const url = `dummy_url&job_id=${String(this.props.currentJob)}`;
const response = await fetch(url, {credentials: 'include'});
const json = await response.json();
const currentJob = (json: CurrentJob); // make the assumption explicit.
console.log(currentJob);
const {location, id, note: ref_note} = currentJob.inventoryJob;
const currentCodes = currentJob.inventoryJobDetails.map(({code, qty}) => ({
code,
qty
}));
this.setState({currentCodes, location, ref_note, id});
const apiBarcodes = currentJob.inventoryJob.history;
if (apiBarcodes.length > 0) {
this.setState({apiBarcodes});
}
this.setState({initialLoad: true});
};
}
Clearly, this is a void function. It has no return statements. However, as an async function, it inherently returns a Promise, just as it did when written as an explicit Promise chain.
Note: void is a construct that has been found useful in Flow and TypeScript to represent the semantic intent of function that do not return values but in reality such functions actually return undefined because, well, this is JavaScript. Flow does not seem to recognize undefined as a type, but under TypeScript, the function could equally be annotated as returning Promise<undefined>. Irregardless, Promise<void> is preferable thanks to the clarity of intent it provides.
Remarks: I worked through this using a combination of https://flow.org/try and the flow binary for Windows. The experience on Windows is really terrible and hopefully it will improve.

When chaining then's, the result will always be a promise.
When calling then, the return value is another promise, otherwise chaining then's wouldn't have been possible.
You can see that easily by using console.log() surrounding the entire chain.