Type error when using example with Typescript

[Uroš Štok]

I've tried the library and it works perfectly with normal js, but throws type errors when using ts.

The type error occurs at addressSchema when passing it to body. Is there something I missed?

Type '{ readonly type: "object"; readonly required: readonly ["number", "street", "type"]; readonly properties: { readonly number: { readonly type: "number"; }; readonly street: { readonly type: "string"; }; readonly type: { ...; }; }; }' is not assignable to type 'ValidateFunction | undefined'.
Type '{ readonly type: "object"; readonly required: readonly ["number", "street", "type"]; readonly properties: { readonly number: { readonly type: "number"; }; readonly street: { readonly type: "string"; }; readonly type: { ...; }; }; }' is not assignable to type 'JSONSchema7'.
Types of property 'required' are incompatible.
The type 'readonly ["number", "street", "type"]' is 'readonly' and cannot be assigned to the mutable type 'string[]'.

import express from "express";
import { Validator, ValidationError } from "express-json-validator-middleware";

const app = express();

app.use(express.json());

const addressSchema = {
  type: "object",
  required: ["number", "street", "type"],
  properties: {
    number: {
      type: "number",
    },
    street: {
      type: "string",
    },
    type: {
      type: "string",
      enum: ["Street", "Avenue", "Boulevard"],
    },
  },
} as const;

const { validate } = new Validator({});

app.post("/address", validate({ body: addressSchema }), (request, response) => {
  response.send({});
});
app.listen(3000);

[Olivier Beaulieu]

I have the same issue - as a workaround, you can use the AllowedSchema, exported from the library, and remove as const:

const addressSchema: AllowedSchema = {

[Simon Plenderleith]

@grawtar @olivierbeaulieu A couple of things will help me investigate this:

• Which version of express-json-validator-middleware are you using?
• Please can you share the tsconfig.json you're using on the project where you see this error.

This issue is likely related to #39.

[Olivier Beaulieu]

I'm using express-json-validator-middleware@2.2.1

And here's my config:

{
  "compilerOptions": {
    "target": "es5",
    "lib": ["dom", "dom.iterable", "esnext"],
    "allowJs": true,
    "skipLibCheck": true,
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "module": "commonjs",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "noEmit": true,
    "jsx": "react",
    "noFallthroughCasesInSwitch": true
  },
  "include": ["./**/*.ts"],
  "exclude": ["node_modules"]
}

[Simon Plenderleith]

@olivierbeaulieu Thank you!

After some discussion on Twitter I've learnt from @i-like-robots that your approach of using the AllowedSchema type is the correct way to do this:

const addressSchema: AllowedSchema = {

I'm going to update the TypeScript part of the README to recommend this instead of as const.