Update documentation

* Add tests for entity-child relationships and removal in world queries, fixed world_each

* Correct test case

---------

Co-authored-by: Marcus <ukendio@gmail.com>

.github/workflows/analysis.yaml

@@ -1,19 +1,19 @@
-name: Analysis
-
-on: [push, pull_request, workflow_dispatch]
-
-jobs:
-  run:
-    name: Run Luau Analyze
-    runs-on: ubuntu-latest
-    
-    steps:
-      - name: Checkout Project
-        uses: actions/checkout@v4
-        
-      - name: Install Luau
-        uses: encodedvenom/install-luau@v2.1
-        
-      - name: Analyze
-        run: |
-          output=$(luau-analyze src || true) # Suppress errors for now.
+name: analysis
+
+on: [push, pull_request, workflow_dispatch]
+
+jobs:
+    run:
+        name: Run Luau Analyze
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout Project
+              uses: actions/checkout@v4
+
+            - name: Install Luau
+              uses: encodedvenom/install-luau@v2.1
+
+            - name: Analyze
+              run: |
+                  output=$(luau-analyze src || true) # Suppress errors for now.

.github/workflows/deploy-docs.yaml

@@ -1,64 +1,64 @@
-# Sample workflow for building and deploying a VitePress site to GitHub Pages
-#
-name: Deploy VitePress site to Pages
-
-on:
-  # Runs on pushes targeting the `main` branch. Change this to `master` if you're
-  # using the `master` branch as the default branch.
-  push:
-    branches: [main]
-
-  # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
-
-# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
-permissions:
-  contents: read
-  pages: write
-  id-token: write
-
-# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
-# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
-concurrency:
-  group: pages
-  cancel-in-progress: false
-
-jobs:
-  # Build job
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 0 # Not needed if lastUpdated is not enabled
-      # - uses: pnpm/action-setup@v3 # Uncomment this if you're using pnpm
-      # - uses: oven-sh/setup-bun@v1 # Uncomment this if you're using Bun
-      - name: Setup Node
-        uses: actions/setup-node@v4
-        with:
-          node-version: 20
-          cache: npm # or pnpm / yarn
-      - name: Setup Pages
-        uses: actions/configure-pages@v4
-      - name: Install dependencies
-        run: npm ci # or pnpm install / yarn install / bun install
-      - name: Build with VitePress
-        run: npm run docs:build # or pnpm docs:build / yarn docs:build / bun run docs:build
-      - name: Upload artifact
-        uses: actions/upload-pages-artifact@v3
-        with:
-          path: docs/.vitepress/dist
-
-  # Deployment job
-  deploy:
-    environment:
-      name: github-pages
-      url: ${{ steps.deployment.outputs.page_url }}
-    needs: build
-    runs-on: ubuntu-latest
-    name: Deploy
-    steps:
-      - name: Deploy to GitHub Pages
-        id: deployment
-        uses: actions/deploy-pages@v4
+# Sample workflow for building and deploying a VitePress site to GitHub Pages
+#
+name: deploy-docs
+
+on:
+    # Runs on pushes targeting the `main` branch. Change this to `master` if you're
+    # using the `master` branch as the default branch.
+    push:
+        branches: [main]
+
+    # Allows you to run this workflow manually from the Actions tab
+    workflow_dispatch:
+
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+permissions:
+    contents: read
+    pages: write
+    id-token: write
+
+# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
+# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
+concurrency:
+    group: pages
+    cancel-in-progress: false
+
+jobs:
+    # Build job
+    build:
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v4
+              with:
+                  fetch-depth: 0 # Not needed if lastUpdated is not enabled
+            # - uses: pnpm/action-setup@v3 # Uncomment this if you're using pnpm
+            # - uses: oven-sh/setup-bun@v1 # Uncomment this if you're using Bun
+            - name: Setup Node
+              uses: actions/setup-node@v4
+              with:
+                  node-version: 20
+                  cache: npm # or pnpm / yarn
+            - name: Setup Pages
+              uses: actions/configure-pages@v4
+            - name: Install dependencies
+              run: npm ci # or pnpm install / yarn install / bun install
+            - name: Build with VitePress
+              run: npm run docs:build # or pnpm docs:build / yarn docs:build / bun run docs:build
+            - name: Upload artifact
+              uses: actions/upload-pages-artifact@v3
+              with:
+                  path: docs/.vitepress/dist
+
+    # Deployment job
+    deploy:
+        environment:
+            name: github-pages
+            url: ${{ steps.deployment.outputs.page_url }}
+        needs: build
+        runs-on: ubuntu-latest
+        name: Deploy
+        steps:
+            - name: Deploy to GitHub Pages
+              id: deployment
+              uses: actions/deploy-pages@v4

.github/workflows/publish-npm.yml

@@ -1,17 +1,17 @@
-name: Publish to NPM
+name: publish-npm
 
 on:
-  push:
-    branches: main
+    push:
+        branches: [main]
 
 jobs:
-  publish:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v3
-        with:
-          node-version: "20"
-      - uses: JS-DevTools/npm-publish@v3
-        with:
-          token: ${{ secrets.NPM_AUTH_TOKEN }}
+    publish:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+            - uses: actions/setup-node@v3
+              with:
+                  node-version: "20"
+            - uses: JS-DevTools/npm-publish@v3
+              with:
+                  token: ${{ secrets.NPM_AUTH_TOKEN }}

.github/workflows/release.yaml

@@ -1,71 +1,71 @@
-name: Release
+name: release
 
 on:
-  push:
-    tags: ["v*"]
+    push:
+        tags: ["v*"]
 
 jobs:
-  build:
-    name: Build
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout Project
-        uses: actions/checkout@v4
+    build:
+        name: Build
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout Project
+              uses: actions/checkout@v4
 
-      - name: Install Rokit
-        uses: CompeyDev/setup-rokit@v0.1.2
+            - name: Install Rokit
+              uses: CompeyDev/setup-rokit@v0.1.2
 
-      - name: Install Dependencies
-        run: wally install
+            - name: Install Dependencies
+              run: wally install
 
-      - name: Build
-        run: rojo build --output build.rbxm default.project.json
+            - name: Build
+              run: rojo build --output build.rbxm default.project.json
 
-      - name: Upload Build Artifact
-        uses: actions/upload-artifact@v3
-        with:
-          name: build
-          path: build.rbxm
+            - name: Upload Build Artifact
+              uses: actions/upload-artifact@v3
+              with:
+                  name: build
+                  path: build.rbxm
 
-  release:
-    name: Release
-    needs: [build]
-    runs-on: ubuntu-latest
-    permissions:
-      contents: write
-    steps:
-      - name: Checkout Project
-        uses: actions/checkout@v4
+    release:
+        name: Release
+        needs: [build]
+        runs-on: ubuntu-latest
+        permissions:
+            contents: write
+        steps:
+            - name: Checkout Project
+              uses: actions/checkout@v4
 
-      - name: Download Jecs Build
-        uses: actions/download-artifact@v3
-        with:
-          name: build
-          path: build
+            - name: Download Jecs Build
+              uses: actions/download-artifact@v3
+              with:
+                  name: build
+                  path: build
 
-      - name: Rename Build
-        run: mv build/build.rbxm jecs.rbxm
+            - name: Rename Build
+              run: mv build/build.rbxm jecs.rbxm
 
-      - name: Create Release
-        uses: softprops/action-gh-release@v1
-        with:
-          name: Jecs ${{ github.ref_name }}
-          files: |
-            jecs.rbxm
+            - name: Create Release
+              uses: softprops/action-gh-release@v1
+              with:
+                  name: Jecs ${{ github.ref_name }}
+                  files: |
+                      jecs.rbxm
 
-  publish:
-    name: Publish
-    needs: [release]
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout Project
-        uses: actions/checkout@v4
+    publish:
+        name: Publish
+        needs: [release]
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout Project
+              uses: actions/checkout@v4
 
-      - name: Install Rokit
-        uses: CompeyDev/setup-rokit@v0.1.2
+            - name: Install Rokit
+              uses: CompeyDev/setup-rokit@v0.1.2
 
-      - name: Wally Login
-        run: wally login --token ${{ secrets.WALLY_AUTH_TOKEN }}
+            - name: Wally Login
+              run: wally login --token ${{ secrets.WALLY_AUTH_TOKEN }}
 
-      - name: Publish
-        run: wally publish
+            - name: Publish
+              run: wally publish

.github/workflows/unit-testing.yaml

@@ -1,31 +1,31 @@
-name: Unit Testing
-
-on: [push, pull_request, workflow_dispatch]
-
-jobs:
-  run:
-    name: Run Luau Tests
-    runs-on: ubuntu-latest
-    timeout-minutes: 2
-
-    steps:
-      - name: Checkout Project
-        uses: actions/checkout@v4
-
-      - name: Install Luau
-        uses: encodedvenom/install-luau@v4.3
-        with:
-          version: 'latest'
-          verbose: 'true'
-
-      - name: Run Unit Tests
-        id: run_tests
-        run: |
-          output=$(luau test/tests.luau)
-          echo "$output"
-          if [[ "$output" == *"0 fails"* ]]; then
-            echo "Unit Tests Passed"
-          else
-            echo "Error: One or More Unit Tests Failed."
-            exit 1
-          fi
+name: unit-testing
+
+on: [push, pull_request, workflow_dispatch]
+
+jobs:
+    run:
+        name: Run Luau Tests
+        runs-on: ubuntu-latest
+        timeout-minutes: 2
+
+        steps:
+            - name: Checkout Project
+              uses: actions/checkout@v4
+
+            - name: Install Luau
+              uses: encodedvenom/install-luau@v4.3
+              with:
+                  version: "latest"
+                  verbose: "true"
+
+            - name: Run Unit Tests
+              id: run_tests
+              run: |
+                  output=$(luau test/tests.luau)
+                  echo "$output"
+                  if [[ "$output" == *"0 fails"* ]]; then
+                    echo "Unit Tests Passed"
+                  else
+                    echo "Error: One or More Unit Tests Failed."
+                    exit 1
+                  fi

docs/api/query.md

@@ -1,88 +1,110 @@
-# Query
-
-A World contains entities which have components. The World is queryable and can be used to get entities with a specific set of components.
-
-# Methods
-
-## with
-Adds components (IDs) to query with, but will not use their data. This is useful for Tags or generally just data you do not care for.
-
-```luau
-function query:with(
-    ...: Entity -- The IDs to query with
-): Query
-```
-
-Example:
-::: code-group
-
-```luau [luau]
-for id, position in world:query(Position):with(Velocity) do
-    -- Do something
-end
-```
-
-```ts [typescript]
-for (const [id, position] of world.query(Position).with(Velocity)) {
-    // Do something
-}
-```
-
-:::
-
-:::info
-Put the IDs inside of `world:query()` instead if you need the data.
-:::
-
-## without
-Removes entities with the provided components from the query.
-
-```luau
-function query:without(
-    ...: Entity -- The IDs to filter against.
-): Query -- Returns the Query
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-for entity, position in world:query(Position):without(Velocity) do
-    -- Do something
-end
-```
-
-```ts [typescript]
-for (const [entity, position] of world.query(Position).without(Velocity)) {
-    // Do something
-}
-```
-:::
-
-## archetypes
-Returns the matching archetypes of the query.
-```luau
-function query:archetypes(): { Archetype }
-```
-
-Example:
-
-```luau [luau]
-for i, archetype in world:query(Position, Velocity):archetypes() do
-    local columns = archetype.columns
-    local field = archetype.records
-
-    local P = field[Position]
-    local V = field[Velocity]
-
-    for row, entity in archetype.entities do
-        local position = columns[P][row]
-        local velocity = columns[V][row]
-        -- Do something
-    end
-end
-```
-
-:::info
-This function is meant for people who want to really customize their query behaviour at the archetype-level
-:::
+# Query
+
+A World contains entities which have components. The World is queryable and can be used to get entities with a specific set of components.
+
+# Methods
+
+## iter
+
+Returns an iterator that can be used to iterate over the query.
+
+```luau
+function Query:iter(): () -> (Entity, ...)
+```
+
+## with
+
+Adds components (IDs) to query with, but will not use their data. This is useful for Tags or generally just data you do not care for.
+
+```luau
+function Query:with(
+    ...: Entity -- The IDs to query with
+): Query
+```
+
+Example:
+::: code-group
+
+```luau [luau]
+for id, position in world:query(Position):with(Velocity) do
+    -- Do something
+end
+```
+
+```ts [typescript]
+for (const [id, position] of world.query(Position).with(Velocity)) {
+	// Do something
+}
+```
+
+:::
+
+:::info
+Put the IDs inside of `world:query()` instead if you need the data.
+:::
+
+## without
+
+Removes entities with the provided components from the query.
+
+```luau
+function Query:without(
+    ...: Entity -- The IDs to filter against.
+): Query -- Returns the Query
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+for entity, position in world:query(Position):without(Velocity) do
+    -- Do something
+end
+```
+
+```ts [typescript]
+for (const [entity, position] of world.query(Position).without(Velocity)) {
+	// Do something
+}
+```
+
+:::
+
+## archetypes
+
+Returns the matching archetypes of the query.
+
+```luau
+function Query:archetypes(): { Archetype }
+```
+
+Example:
+
+```luau [luau]
+for i, archetype in world:query(Position, Velocity):archetypes() do
+    local columns = archetype.columns
+    local field = archetype.records
+
+    local P = field[Position]
+    local V = field[Velocity]
+
+    for row, entity in archetype.entities do
+        local position = columns[P][row]
+        local velocity = columns[V][row]
+        -- Do something
+    end
+end
+```
+
+:::info
+This function is meant for people who want to really customize their query behaviour at the archetype-level
+:::
+
+## cached
+
+Returns a cached version of the query. This is useful if you want to iterate over the same query multiple times.
+
+```luau
+function Query:cached(): Query -- Returns the cached Query
+```

docs/api/world.md

@@ -1,402 +1,500 @@
-# World
-A World contains entities which have components. The World is queryable and can be used to get entities with a specific set of components and to perform different kinds of operations on them.
-
-# Functions
-## new
-`World` utilizes a class, meaning JECS allows you to create multiple worlds.
-```luau
-function World.new(): World
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local world = jecs.World.new()
-local myOtherWorld = jecs.World.new()
-```
-
-```ts [typescript]
-import { World } from "@rbxts/jecs";
-
-const world = new World();
-const myOtherWorld = new World();
-```
-:::
-
-# Methods
-## entity
-Creates a new entity.
-```luau
-function World:entity(): Entity
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local entity = world:entity()
-```
-
-```ts [typescript]
-const entity = world.entity();
-```
-:::
-
-## component
-Creates a new component. Do note components are entities as well, meaning JECS allows you to add other components onto them.
-
-These are meant to be added onto other entities through `add` and `set`
-```luau
-function World:component<T>(): Entity<T> -- The new componen.
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local Health = world:component() :: jecs.Entity<number> -- Typecasting this will allow us to know what kind of data the component holds!
-```
-
-```ts [typescript]
-const Health = world.component<number>();
-```
-:::
-
-## get
-Returns the data present in the component that was set in the entity. Will return nil if the component was a tag or is not present.
-```luau
-function World:get<T>(
-    entity: Entity, -- The entity
-    id: Entity<T> -- The component ID to fetch
-): T?
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local Health = world:component() :: jecs.Entity<number>
-
-local Entity = world:entity()
-world:set(Entity, Health, 100)
-
-print(world:get(Entity, Health))
-
--- Outputs:
--- 100
-```
-
-```ts [typescript]
-const Health = world.component<number>();
-
-const Entity = world.entity();
-world.set(Entity, Health, 100);
-
-print(world.get(Entity, Health))
-
-// Outputs:
-// 100
-```
-:::
-
-## has
-Returns whether an entity has a component (ID). Useful for checking if an entity has a tag or if you don't care of the data that is inside the component.
-```luau
-function World:has(
-    entity: Entity, -- The entity
-    id: Entity<T> -- The component ID to check
-): boolean
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local IsMoving = world:component()
-local Ragdolled = world:entity() -- This is a tag, meaning it won't contain data
-local Health = world:component() :: jecs.Entity<number>
-
-local Entity = world:entity()
-world:set(Entity, Health, 100)
-world:add(Entity, Ragdolled)
-
-print(world:has(Entity, Health))
-print(world:has(Entity, IsMoving)
-
-print(world:get(Entity, Ragdolled))
-print(world:has(Entity, Ragdolled))
-
--- Outputs:
--- true
--- false
--- nil
--- true
-```
-
-```ts [typescript]
-const IsMoving = world.component();
-const Ragdolled = world.entity(); // This is a tag, meaning it won't contain data
-const Health = world.component<number>();
-
-const Entity = world.entity();
-world.set(Entity, Health, 100);
-world.add(Entity, Ragdolled);
-
-print(world.has(Entity, Health));
-print(world.has(Entity, IsMoving));
-
-print(world.get(Entity, Ragdolled));
-print(world.has(Entity, Ragdolled));
-
-// Outputs:
-// true
-// false
-// nil
-// true
-```
-:::
-
-## add
-Adds a component (ID) to the entity. Useful for adding a tag to an entity, as this adds the component to the entity without any additional values inside
-
-```luau
-function World:add(
-    entity: Entity, -- The entity
-    id: Entity<T> -- The component ID to add
-): void
-```
-
-::: info
-This function is idempotent, meaning if the entity already has the id, this operation will have no side effects.
-:::
-
-## set
-Adds or changes data in the entity's component.
-```luau
-function World:set(
-    entity: Entity, -- The entity
-    id: Entity<T>, -- The component ID to set
-    data: T -- The data of the component's type
-): void
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local Health = world:component() :: jecs.Entity<number>
-
-local Entity = world:entity()
-world:set(Entity, Health, 100)
-
-print(world:get(Entity, Health))
-
-world:set(Entity, Health, 50)
-print(world:get(Entity, Health))
-
--- Outputs:
--- 100
--- 50
-```
-
-```ts [typescript]
-const Health = world.component<number>();
-
-const Entity = world.entity();
-world.set(Entity, Health, 100);
-
-print(world.get(Entity, Health)) 
-
-world.set(Entity, Health, 50);
-print(world.get(Entity, Health))
-
-// Outputs:
-// 100
-// 50
-```
-:::
-
-## query
-Creates a [`query`](query) with the given components (IDs). Entities that satisfies the conditions of the query will be returned and their corresponding data.
-```luau
-function World:query(
-    ...: Entity -- The components to query with
-): Query
-```
-
-Example:
-
-::: code-group
-```luau [luau]
--- Entity could also be a component if a component also meets the requirements, since they are also entities which you can add more components onto
-for entity, position, velocity in world:query(Position, Velocity) do
-	
-end
-```
-
-```ts [typescript]
-// Roblox-TS allows to deconstruct tuples on the act like if they were arrays!
-// Entity could also be a component if a component also meets the requirements, since they are also entities which you can add more components onto
-for (const [entity, position, velocity] of world.query(Position, Velocity) {
-    // Do something
-}
-```
-:::
-
-:::info
-Queries are uncached by default, this is generally very cheap unless you have high fragmentation from e.g. relationships.
-
-:::
-## target
-Get the target of a relationship.
-This will return a target (second element of a pair) of the entity for the specified relationship. The index allows for iterating through the targets, if a single entity has multiple targets for the same relationship.
-If the index is larger than the total number of instances the entity has for the relationship or if there is no pair with the specified relationship on the entity, the operation will return nil.
-```luau
-function World:target(
-    entity: Entity, -- The entity
-    relation: Entity, -- The relationship between the entity and the target
-    nth: number, -- The index
-): Entity? -- The target for the relationship at the specified index.
-```
-
-## parent
-Get parent (target of ChildOf relationship) for entity. If there is no ChildOf relationship pair, it will return nil.
-```luau
-function World:parent(
-    child: Entity -- The child ID to find the parent of
-): Entity? -- Returns the parent of the child
-```
-
-This operation is the same as calling:
-
-```luau
-world:target(entity, jecs.ChildOf, 0)
-```
-
-## contains
-Checks if an entity or component (id) exists in the world.
-```luau
-function World:contains(
-    entity: Entity,
-): boolean
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local entity = world:entity()
-print(world:contains(entity))
-print(world:contains(1))
-print(world:contains(2))
-
--- Outputs:
--- true
--- true
--- false
-```
-
-```ts [typescript]
-const entity = world.entity();
-print(world.contains(entity));
-print(world.contains(1));
-print(world.contains(2));
-
-// Outputs:
-// true
-// true
-// false
-```
-:::
-
-## remove
-Removes a component (ID) from an entity
-```luau
-function World:remove(
-    entity: Entity,
-	component: Entity<T>
-): void
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local IsMoving = world:component()
-
-local entity = world:entity()
-world:add(entity, IsMoving)
-
-print(world:has(entity, IsMoving)) 
-
-world:remove(entity, IsMoving)
-print(world:has(entity, IsMoving))
-
--- Outputs:
--- true
--- false
-```
-
-```ts [typescript]
-const IsMoving = world.component();
-
-const entity = world.entity();
-world.add(entity, IsMoving);
-
-print(world.has(entity, IsMoving));
-
-world.remove(entity, IsMoving);
-print(world.has(entity, IsMoving));
-
-// Outputs:
-// true
-// false
-```
-:::
-
-## delete
-Deletes an entity and all of its related components and relationships.
-```luau
-function World:delete(
-    entity: Entity
-): void
-```
-
-Example:
-
-::: code-group
-```luau [luau]
-local entity = world:entity()
-print(world:has(entity))
-
-world:delete(entity)
-
-print(world:has(entity))
-
--- Outputs:
--- true
--- false
-```
-
-```ts [typescript]
-const entity = world.entity();
-print(world.has(entity));
-
-world.delete(entity);
-
-print(world.has(entity));
-
-// Outputs:
-// true
-// false
-```
-:::
-
-## clear
-Clears all of the components and relationships of the entity without deleting it.
-```luau
-function World:clear(
-    entity: Entity
-): void
-```
+# World
+
+A World contains entities which have components. The World is queryable and can be used to get entities with a specific set of components and to perform different kinds of operations on them.
+
+# Functions
+
+## new
+
+`World` utilizes a class, meaning JECS allows you to create multiple worlds.
+
+```luau
+function World.new(): World
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local world = jecs.World.new()
+local myOtherWorld = jecs.World.new()
+```
+
+```ts [typescript]
+import { World } from "@rbxts/jecs";
+
+const world = new World();
+const myOtherWorld = new World();
+```
+
+:::
+
+# Methods
+
+## entity
+
+Creates a new entity.
+
+```luau
+function World:entity(): Entity
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local entity = world:entity()
+```
+
+```ts [typescript]
+const entity = world.entity();
+```
+
+:::
+
+## component
+
+Creates a new component. Do note components are entities as well, meaning JECS allows you to add other components onto them.
+
+These are meant to be added onto other entities through `add` and `set`
+
+```luau
+function World:component<T>(): Entity<T> -- The new componen.
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local Health = world:component() :: jecs.Entity<number> -- Typecasting this will allow us to know what kind of data the component holds!
+```
+
+```ts [typescript]
+const Health = world.component<number>();
+```
+
+:::
+
+## get
+
+Returns the data present in the component that was set in the entity. Will return nil if the component was a tag or is not present.
+
+```luau
+function World:get<T>(
+    entity: Entity, -- The entity
+    id: Entity<T> -- The component ID to fetch
+): T?
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local Health = world:component() :: jecs.Entity<number>
+
+local Entity = world:entity()
+world:set(Entity, Health, 100)
+
+print(world:get(Entity, Health))
+
+-- Outputs:
+-- 100
+```
+
+```ts [typescript]
+const Health = world.component<number>();
+
+const Entity = world.entity();
+world.set(Entity, Health, 100);
+
+print(world.get(Entity, Health));
+
+// Outputs:
+// 100
+```
+
+:::
+
+## has
+
+Returns whether an entity has a component (ID). Useful for checking if an entity has a tag or if you don't care of the data that is inside the component.
+
+```luau
+function World:has(
+    entity: Entity, -- The entity
+    id: Entity<T> -- The component ID to check
+): boolean
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local IsMoving = world:component()
+local Ragdolled = world:entity() -- This is a tag, meaning it won't contain data
+local Health = world:component() :: jecs.Entity<number>
+
+local Entity = world:entity()
+world:set(Entity, Health, 100)
+world:add(Entity, Ragdolled)
+
+print(world:has(Entity, Health))
+print(world:has(Entity, IsMoving)
+
+print(world:get(Entity, Ragdolled))
+print(world:has(Entity, Ragdolled))
+
+-- Outputs:
+-- true
+-- false
+-- nil
+-- true
+```
+
+```ts [typescript]
+const IsMoving = world.component();
+const Ragdolled = world.entity(); // This is a tag, meaning it won't contain data
+const Health = world.component<number>();
+
+const Entity = world.entity();
+world.set(Entity, Health, 100);
+world.add(Entity, Ragdolled);
+
+print(world.has(Entity, Health));
+print(world.has(Entity, IsMoving));
+
+print(world.get(Entity, Ragdolled));
+print(world.has(Entity, Ragdolled));
+
+// Outputs:
+// true
+// false
+// nil
+// true
+```
+
+:::
+
+## add
+
+Adds a component (ID) to the entity. Useful for adding a tag to an entity, as this adds the component to the entity without any additional values inside
+
+```luau
+function World:add(
+    entity: Entity, -- The entity
+    id: Entity<T> -- The component ID to add
+): void
+```
+
+::: info
+This function is idempotent, meaning if the entity already has the id, this operation will have no side effects.
+:::
+
+## set
+
+Adds or changes data in the entity's component.
+
+```luau
+function World:set(
+    entity: Entity, -- The entity
+    id: Entity<T>, -- The component ID to set
+    data: T -- The data of the component's type
+): void
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local Health = world:component() :: jecs.Entity<number>
+
+local Entity = world:entity()
+world:set(Entity, Health, 100)
+
+print(world:get(Entity, Health))
+
+world:set(Entity, Health, 50)
+print(world:get(Entity, Health))
+
+-- Outputs:
+-- 100
+-- 50
+```
+
+```ts [typescript]
+const Health = world.component<number>();
+
+const Entity = world.entity();
+world.set(Entity, Health, 100);
+
+print(world.get(Entity, Health));
+
+world.set(Entity, Health, 50);
+print(world.get(Entity, Health));
+
+// Outputs:
+// 100
+// 50
+```
+
+:::
+
+## query
+
+Creates a [`query`](query) with the given components (IDs). Entities that satisfies the conditions of the query will be returned and their corresponding data.
+
+```luau
+function World:query(
+    ...: Entity -- The components to query with
+): Query
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+-- Entity could also be a component if a component also meets the requirements, since they are also entities which you can add more components onto
+for entity, position, velocity in world:query(Position, Velocity) do
+
+end
+```
+
+```ts [typescript]
+// Roblox-TS allows to deconstruct tuples on the act like if they were arrays!
+// Entity could also be a component if a component also meets the requirements, since they are also entities which you can add more components onto
+for (const [entity, position, velocity] of world.query(Position, Velocity) {
+    // Do something
+}
+```
+
+:::
+
+:::info
+Queries are uncached by default, this is generally very cheap unless you have high fragmentation from e.g. relationships.
+
+:::
+
+## target
+
+Get the target of a relationship.
+This will return a target (second element of a pair) of the entity for the specified relationship. The index allows for iterating through the targets, if a single entity has multiple targets for the same relationship.
+If the index is larger than the total number of instances the entity has for the relationship or if there is no pair with the specified relationship on the entity, the operation will return nil.
+
+```luau
+function World:target(
+    entity: Entity, -- The entity
+    relation: Entity, -- The relationship between the entity and the target
+    nth: number, -- The index
+): Entity? -- The target for the relationship at the specified index.
+```
+
+## parent
+
+Get parent (target of ChildOf relationship) for entity. If there is no ChildOf relationship pair, it will return nil.
+
+```luau
+function World:parent(
+    child: Entity -- The child ID to find the parent of
+): Entity? -- Returns the parent of the child
+```
+
+This operation is the same as calling:
+
+```luau
+world:target(entity, jecs.ChildOf, 0)
+```
+
+## contains
+
+Checks if an entity or component (id) exists in the world.
+
+```luau
+function World:contains(
+    entity: Entity,
+): boolean
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local entity = world:entity()
+print(world:contains(entity))
+print(world:contains(1))
+print(world:contains(2))
+
+-- Outputs:
+-- true
+-- true
+-- false
+```
+
+```ts [typescript]
+const entity = world.entity();
+print(world.contains(entity));
+print(world.contains(1));
+print(world.contains(2));
+
+// Outputs:
+// true
+// true
+// false
+```
+
+:::
+
+## remove
+
+Removes a component (ID) from an entity
+
+```luau
+function World:remove(
+    entity: Entity,
+	component: Entity<T>
+): void
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local IsMoving = world:component()
+
+local entity = world:entity()
+world:add(entity, IsMoving)
+
+print(world:has(entity, IsMoving))
+
+world:remove(entity, IsMoving)
+print(world:has(entity, IsMoving))
+
+-- Outputs:
+-- true
+-- false
+```
+
+```ts [typescript]
+const IsMoving = world.component();
+
+const entity = world.entity();
+world.add(entity, IsMoving);
+
+print(world.has(entity, IsMoving));
+
+world.remove(entity, IsMoving);
+print(world.has(entity, IsMoving));
+
+// Outputs:
+// true
+// false
+```
+
+:::
+
+## delete
+
+Deletes an entity and all of its related components and relationships.
+
+```luau
+function World:delete(
+    entity: Entity
+): void
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local entity = world:entity()
+print(world:has(entity))
+
+world:delete(entity)
+
+print(world:has(entity))
+
+-- Outputs:
+-- true
+-- false
+```
+
+```ts [typescript]
+const entity = world.entity();
+print(world.has(entity));
+
+world.delete(entity);
+
+print(world.has(entity));
+
+// Outputs:
+// true
+// false
+```
+
+:::
+
+## clear
+
+Clears all of the components and relationships of the entity without deleting it.
+
+```luau
+function World:clear(
+    entity: Entity
+): void
+```
+
+## each
+
+Iterate over all entities with the specified component.
+Useful when you only need the entity for a specific ID and you want to avoid creating a query.
+
+```luau
+function World:each(
+	id: Entity -- The component ID
+): () -> Entity
+```
+
+Example:
+
+::: code-group
+
+```luau [luau]
+local id = world:entity()
+for entity in world:each(id) do
+	-- Do something
+end
+```
+
+```ts [typescript]
+const id = world.entity();
+for (const entity of world.each(id)) {
+	// Do something
+}
+```
+
+:::
+
+## children
+
+Iterate entities in root of parent
+
+```luau
+function World:children(
+	parent: Entity -- The parent entity
+): () -> Entity
+```
+
+This is the same as calling:
+
+```luau
+world:each(pair(ChildOf, parent))
+```

jecs.luau

@@ -1995,6 +1995,7 @@ local function world_each(world: World, id): () -> ()
 			archetype = archetypes[archetype_id]
 			entities = archetype.entities
 			row = #entities
+			entity = entities[row]
 		end
 		row -= 1
 		return entity

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "@rbxts/jecs",
-	"version": "0.5.1",
+	"version": "0.5.2",
 	"description": "Stupidly fast Entity Component System",
 	"main": "jecs.luau",
 	"repository": {

test/tests.luau

@@ -900,20 +900,39 @@ end)
 
 TEST("world:children", function()
 	local world = world_new()
-	local e1 = world:entity()
-	local e2 = world:entity()
-	local e3 = world:entity()
+	local C = world:component()
+	local T = world:entity()
 
+	local e1 = world:entity()
+	world:set(e1, C, true)
+
+	local e2 = world:entity()
+
+	world:add(e2, T)
 	world:add(e2, pair(ChildOf, e1))
+
+	local e3 = world:entity()
 	world:add(e3, pair(ChildOf, e1))
 
-	for entity in world:children(pair(ChildOf, e1)) do
+	local count = 0
+	for entity in world:children(e1) do
+		count += 1
 		if entity == e2 or entity == e3 then
 			CHECK(true)
 			continue
 		end
 		CHECK(false)
 	end
+	CHECK(count == 2)
+
+	world:remove(e2, pair(ChildOf, e1))
+
+	count = 0
+	for entity in world:children(e1) do
+		count += 1
+	end
+
+	CHECK(count == 1)
 end)
 
 TEST("world:clear()", function()
@@ -1562,9 +1581,9 @@ TEST("repro", function()
 		local world = world_new()
 		local component1 = world:component()
 		local tag1 = world:entity()
-		
+
 		local query = world:query(component1):with(tag1):cached()
-		
+
 		local entity = world:entity()
 		world:set(entity, component1, "some data")
 

wally.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ukendio/jecs"
-version = "0.5.1"
+version = "0.5.2"
 registry = "https://github.com/UpliftGames/wally-index"
 realm = "shared"
 license = "MIT"