feat: $discriminate with runtime check (v2.0.0)

.github/workflows/build.yml

@@ -1,17 +1,17 @@
 name: build
 
 on:
-  - push
-  - pull_request
+    - push
+    - pull_request
 
 jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-node@v3
-        with:
-          node-version: 16
-          cache: yarn
-      - run: yarn install
-      - run: yarn build
+    build:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v3
+            - uses: actions/setup-node@v3
+              with:
+                  node-version: 20
+                  cache: yarn
+            - run: yarn install
+            - run: yarn build

.github/workflows/npm-publish.yml

@@ -1,20 +1,20 @@
 name: Publish to NPM
 
 on:
-  release:
-    types: [created]
+    release:
+        types: [created]
 
 jobs:
-  publish-npm:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-node@v3
-        with:
-          node-version: 16
-          registry-url: https://registry.npmjs.org/
-          cache: yarn
-      - run: yarn install
-      - run: yarn publish --access public
-        env:
-          NODE_AUTH_TOKEN: ${{secrets.npm_token}}
+    publish-npm:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v3
+            - uses: actions/setup-node@v3
+              with:
+                  node-version: 20
+                  registry-url: https://registry.npmjs.org/
+                  cache: yarn
+            - run: yarn install
+            - run: yarn publish --access public
+              env:
+                  NODE_AUTH_TOKEN: ${{secrets.npm_token}}

.github/workflows/test.yml

@@ -1,17 +1,17 @@
 name: test
 
 on:
-  - push
-  - pull_request
+    - push
+    - pull_request
 
 jobs:
-  test:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-node@v3
-        with:
-          node-version: 16
-          cache: yarn
-      - run: yarn install
-      - run: yarn test
+    test:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v3
+            - uses: actions/setup-node@v3
+              with:
+                  node-version: 20
+                  cache: yarn
+            - run: yarn install
+            - run: yarn test

.gitignore

@@ -1,8 +1,8 @@
 # build
-lib/
+dist/
 
 # dependencies
 node_modules/
 
 # editor
-.idea/
+.idea/

.prettierignore

@@ -0,0 +1,25 @@
+node_modules
+build
+dist
+storybook-static
+.next
+.turbo
+.yarn
+
+package.json
+
+# Lockfiles
+package-lock.json
+pnpm-lock.yaml
+yarn.lock
+
+# Generated files
+generated
+__generated__
+*.generated*
+
+# IDE
+.idea
+.vscode
+
+.DS_Store

README.md

@@ -16,12 +16,12 @@ yarn add @atmina/formbuilder
 `FormBuilder` exposes a single hook `useFormBuilder` which is mostly compatible with `useForm` from `react-hook-form`.
 It contains an additional member, `fields`, which represents an alternative, object-oriented API on top of React Hook
 Form. Each field in the form data can be accessed as a property, including nested fields. The field can be called as a
-function to [register](https://react-hook-form.com/api/useform/register/) an input. It also exposes RHF functions via 
+function to [register](https://react-hook-form.com/api/useform/register/) an input. It also exposes RHF functions via
 field-level methods, e.g. `$setValue`. These methods are prefixed with `$` to prevent potential conflicts with form
 data members.
 
 ```tsx
-import { useFormBuilder } from '@atmina/formbuilder';
+import {useFormBuilder} from '@atmina/formbuilder';
 
 interface Address {
     state: string;
@@ -31,43 +31,51 @@ interface Address {
 }
 
 const App = () => {
-    const {fields, handleSubmit} = useFormBuilder<{name: string, address: Address}>();
-
+    const {fields, handleSubmit} = useFormBuilder<{
+        name: string;
+        address: Address;
+    }>();
+
     const handleFormSubmit = handleSubmit((data) => {
-       console.log(data);
+        console.log(data);
     });
-    
+
     return (
         <form onSubmit={handleFormSubmit}>
             <input {...fields.name()} />
             <input {...fields.address.city()} />
             {/* etc. */}
         </form>
     );
-
-
-}
+};
 ```
 
 ## Fields
 
-You can create components that encapsulate a single (typed) field by accepting a `FormBuilder<T>` prop  where `T` is
+You can create components that encapsulate a single (typed) field by accepting a `FormBuilder<T>` prop where `T` is
 the type of the field. We like to call this `on` or `field`, but you are free to name it however you like.
 
 ```tsx
-import { FC } from "react";
+import {FC} from 'react';
 
-const TextField: FC<{on: FormBuilder<string>, label: string}> = ({on: field}) => {
-    return <div>
-        <label>
-            <span>{label}</span>
-            <input type="text" {...field()} />
-        </label>
-        <button type="button" onClick={() => field.$setValue(getRandomName())}>
-          Randomize
-        </button>
-    </div>
-}
+const TextField: FC<{on: FormBuilder<string>; label: string}> = ({
+    on: field,
+}) => {
+    return (
+        <div>
+            <label>
+                <span>{label}</span>
+                <input type='text' {...field()} />
+            </label>
+            <button
+                type='button'
+                onClick={() => field.$setValue(getRandomName())}
+            >
+                Randomize
+            </button>
+        </div>
+    );
+};
 ```
 
 The field component would be used like this:
@@ -86,15 +94,17 @@ You can create components which encapsulate a group of related fields, such as a
 composition, letting you piece together complex data structures and adding a lot of reusability to your forms.
 
 ```tsx
-import { FC } from "react";
+import {FC} from 'react';
 
 const AddressSubform: FC<{field: FormBuilder<Address>}> = ({field}) => {
-    return <div>
-        <TextField label="State" field={field.state} />
-        <TextField label="City" field={field.city} />
-        {/* etc. */}
-    </div>
-}
+    return (
+        <div>
+            <TextField label='State' field={field.state} />
+            <TextField label='City' field={field.city} />
+            {/* etc. */}
+        </div>
+    );
+};
 ```
 
 ## Field arrays
@@ -127,27 +137,34 @@ wrap the primitive in an object, or use a controller (`$useController`) to imple
 
 For more information, see the React Hook Form docs on [`useFieldArray`](https://react-hook-form.com/docs/usefieldarray).
 
-## Discriminating unions
+## Discriminated unions
 
 In case of a form that contains fields with object unions, the `$discriminate()` function may be used to narrow the type
 using a specific member like this:
 
 ```tsx
-import { FC } from 'react';
-
-type DiscriminatedForm = 
-    | { __typename: 'foo'; foo: string; }
-    | { __typename: 'bar'; bar: number; }
-
-const DiscriminatedSubform: FC<{field: FormBuilder<DiscriminatedForm>}> = ({field}) => {
-    const fooForm = field.$discriminate('__typename', 'foo');
-
-    return <input {...fooForm.foo()} />;
+import {FC} from 'react';
+
+type DiscriminatedForm =
+    | {__typename: 'foo'; foo: string}
+    | {__typename: 'bar'; bar: number};
+
+const DiscriminatedSubform: FC<{field: FormBuilder<DiscriminatedForm>}> = ({
+    field,
+}) => {
+    const [typename, narrowed] = field.$discriminate('__typename');
+
+    switch (typename) {
+      case 'foo':
+        return <input {...narrowed.foo()} />;
+      case 'bar':
+        // ...
+    }
 };
 ```
 
-> [!IMPORTANT]
-> `$discriminate` currently does **not** perform any runtime checks, it's strictly used for type narrowing at this time.
+This returns the current value of the discriminator as well as a `FormBuilder` that is automatically narrowed when
+the discriminator is checked, for example in a `switch` or `if` block.
 
 ## Compatibility with `useForm`
 
@@ -156,7 +173,6 @@ Currently, `useFormBuilder` is almost compatible with `useForm`. This means you
 `useFormBuilder`. However, future versions of the library may see us diverging further from `useForm` in an effort to
 streamline this API and increase its type-safety.
 
-
 ## License
 
 MIT

eslint.config.js

@@ -0,0 +1,7 @@
+/**
+ * @type {import('eslint').Linter.FlatConfig[]}
+ */
+module.exports = [
+  ...require('@atmina/linting/eslint/recommended'),
+  require('@atmina/linting/eslint/react'),
+];

jest.config.js

@@ -1,6 +1,5 @@
 /** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
 module.exports = {
-  preset: "ts-jest",
-  testEnvironment: "jsdom",
-  setupFilesAfterEnv: ["@testing-library/jest-dom/extend-expect"],
+  preset: 'ts-jest',
+  testEnvironment: 'jsdom'
 };