What is Quel

Quel is declarative, simple, easy, pure javascript frontend framework.

Our goal

The development goal is to simplify the increasingly complex frontend development.

The main features

Minimal rules and conventions, as intuitive as possible
Declarative view descriptions
Support two way binding
No need for other libraries
No need for transpiling
Component-based
Complete separation of CSS, HTML and State
Compliant with web standards
Support single file component like a .svelte and .vue
Property description by dot notation

Simple and declarative view

<div>
  <form data-bind="add|preventDefault">
    <input data-bind="task">
    <button data-bind="disabled:task|falsey">add</button>
  </form>
</div>
<ul>
  {{ loop:taskList }}
  <li data-bind="onclick:select">
    <span data-bind="class.selected:taskList.*.selected">{{ taskList.* }}</span>, 
    <button data-bind="delete">X</button>
  </li>
  {{ endloop: }}
</ul>

Simple class to store and manipulate state

class State {
  task = "";
  taskList = [];
  selectedIndex;
  get "taskList.*.selected"() {
    return this.selectedIndex === this.$1;
  }

  add() {
    this.taskList = this.taskList.concat(this.task);
    this.task = "";
  }

  delete(e, $1) {
    this.taskList = this.taskList.toSpliced($1, 1);
    this.selectedIndex = undefined;
  }

  select(e, $1) {
    this.selectedIndex = $1;
  }

  /** @type {{string,string[]}} special property, describe dependent properties */
  $dependentProps = {
    "taskList.*.selected": [ "selectedIndex" ],
  }
}

See todo list sample

Getting Start

To use Quel, import the necessary functions from the CDN or the downloaded file using the import declaration.

An import declaration is required, so the script tag needs type="module".

Example for CDN

<script type="module">
import { registerComponentModules } from "https://cdn.jsdelivr.net/gh/mogera551/quel@latest/dist/quel.min.js"; // CDN
</script>

Example for downloaded file

<script type="module">
import { registerComponentModules } from "./path/to/quel.min.js"; // path to downloaded file
</script>

Install Test

Display Welcome to Quel.

<!DOCTYPE html>
<html lang="ja">
<meta charset="utf-8">

<myapp-main></myapp-main>

<script type="module">
import { registerComponentModules } from "https://cdn.jsdelivr.net/gh/mogera551/quel@latest/dist/quel.min.js"; // CDN

const html = `
<div>{{ message }}</div>
`;

class State {
  message = "Welcome to Quel";
}

registerComponentModules({ myappMain:{ html, State } });
</script>
</html>

The development flow

In component-based development, you will proceed with the following steps:

Write custom elements in HTML
Create corresponding component modules
- Define the HTML template
- Define the class to store and manipulate state
Associate custom elements with component modules

Write custom elements in HTML

You can use autonomous custom elements and customized built-in elements for custom elements. The custom element name must include a dash -.

Example for custom elements index.html

<!DOCTYPE html>
<html lang="ja">
<meta charset="utf-8">

<!-- autonomous custom element -->
<myapp-main><myapp-main>

<!-- customized built-in element -->
<div is="myapp-main"></div>

</html>

Create corresponding single file component

A single file component consists of a class that stores and manipulates state, an HTML template, an css. Here, it is referred to as main.sfc.html.

example

<script type="module">
export class State {
  message = "welcome to quel";
}
</script>

<div class="message">{{ message }}</div>

<style>
div.message {
  color: red;
}
</style>

Define the class to store and manipulate state

Define the State class that stores and manipulates the state of the component. Use script tag with type="module" attribute. By declaring members that store state as fields within the class, you can handle the state as properties of the class. Create methods within the class to manipulate the state. Declare with the class name State and export it. You can also use accessor properties using getters. note:When using accessor properties, it is necessary to define dependencies.

Example for State class of single file component main.sfc.html

<script type="module">
export class State {
  message = "welcome to quel";
  count = 0;
  animals = [{ name:"dog" }, { name:"cat" }, { name:"mouse" }];
  countUp() {
    count++;
  }
}
</script>

Define the HTML template.

Define the HTML that will serve as the content of the component. You describe the embedding of properties defined in the State class, the association of attribute values of html elements, the association of events, conditional branching, and repetition.

Example for HTML template of signle file component main.sfc.html


<div class="message">{{ message }}</div>

<button data-bind="countUp">count up, count={{ count }}</button>

{{ if:count|gt,0 }}
  count > 0
{{ else: }}
  count = 0
{{ endif: }}

{{ loop:animals }}
  <div>{{ animals.*.name }}</div>
{{ endloop: }}

Define the CSS.

Define the CSS that will serve as the content of the component. Use style tag.

Example for HTML template of signle file component main.sfc.html

<style>
div.message {
  color: red;
}
</style>

Associate custom elements with component modules

You associate the single file component with the custom element name using the registerSingleFileComponents function.

index.html

import { registerSingleFileComponents } from "https://cdn.jsdelivr.net/gh/mogera551/quel@latest/dist/quel.min.js"; // CDN

registerSingleFileComponents({ "myapp-main":"./main.sfc.html" });

Tutorial

First

The file structure used in the tutorial is as follows.

--+-- index.html
  |
  +-- main.sfc.html

In index.html

Describe the custom element ()
Import registerSingleFileComponents function
associate the single file component with the custom element name using the registerSingleFileComponents function

Unless otherwise stated, the tutorial will use the contents of the following index.html.

index.html

<!DOCTYPE html>
<html lang="ja">
<meta charset="utf-8">

<myapp-main></myapp-main>

<script type="module">
import { registerSingleFileComponents } from "https://cdn.jsdelivr.net/gh/mogera551/quel@latest/dist/quel.min.js"; // CDN

registerComponentModules({ "myapp-main": "./main.sfc.html" });
</script>
</html>

In main.sfc.html,

You define the HTML template in the html variable, export it
In the State class, you define a class that stores and manipulates state, export it.

In the tutorial, we will mainly discuss main.sfc.html.

main.sfc.html

<script type="module">
export class State {
  // (State)

  // (Manupilate)

}
</script>

(HTML Tempate)

Step 1. Embedding properties

In html, enclose the property message to be embedded in {{ }}.
In State, declare the property message that stores the state as a field, and give it an initial value of welcome to quel.
The State class is extended by a Proxy after it is instantiated, so you cannot use private fields in the State class.
Property names starting with $ are assigned to special properties, so you cannot use them.

Example main.sfc.html

<script type="module">
export class State {
  message = "welcome to quel";
  // #message NG, cannot use private fields
  // $message NG, cannot use name starting with $ 
}
</script>

<div>{{ message }}</div>

See result.

See source.

Step 2. Property Binding

Associate the properties of the html elements in template with the properties of the ViewModel class.
Specify (element property name):(ViewModel class property name) in the data-bind attribute of the element. textContent:message,value:message,value:season...
If you specify multiple bindings, separate them with a semicolon ;. disabled:buttonDisable; textContent:season;
When a property of the ViewModel class is updated, the update is automatically reflected in the property of the html element.
For input elements, the property of the ViewModel class is updated according to the input value. (See bidirectional binding)

The content of the html variable in main.js

<div>
  <div>{{ message }}</div>
  <!-- bind ViewModel.message to div.textContent -->
  <div data-bind="textContent:message"></div>
  <!-- input element, bind ViewModel.message to input.value -->
  <input type="text" data-bind="value:message">
</div>
<div>
  <div>{{ season }}</div>
  <!-- input element, bind ViewModel.season to select.value -->
  <select data-bind="value:season">
    <option value="spring">spring</option>
    <option value="summer">summer</option>
    <option value="autumn">autumn</option>
    <option value="winter">winter</option>
  </select>
</div>
<div>
  <!-- bind ViewModel.buttonDisable to button.disabled -->
  <!-- bind ViewModel.season to button.textContent -->
  <button data-bind="disabled:buttonDisable; textContent:season;"></button>
  <label>
    <!-- input element, bind ViewModel.buttonDisable to input.checked -->
    <input type="checkbox" data-bind="checked:buttonDisable">
    button disable
  </label>
</div>

The ViewModel class in main.js

export class ViewModel {
  message = "welcome to quel";
  season = "spring";
  buttonDisable = false;
}

See result.

See source.

Step 3. Event Binding

Associate the event properties (on~) of the html elements with the methods of the ViewModel class.
Specify (element event property name):(ViewModel class method name) in the data-bind attribute of the element. ->onclick:popup
The methods of the ViewModel class take an Event object as an argument. ->checked(e)

Content of the html variable in main.js

<button type="button" data-bind="onclick:popup">click here</button>
<label>
  <input type="checkbox" data-bind="onclick:checked">checked
</label>

ViewModel class in main.js

export class ViewModel {
  popup() {
    alert("popup!!!");
  }

  /**
   * @param {Event} e Event object
   */
  checked(e) {
    alert(`checked ${e.target.checked ? "on" : "off"}`);
  }
}

See result.

See source.

Step 4. Accessor Properties

You can also embed and bind accessor properties using get.
When using accessor properties, you need to describe the dependencies in the $dependentProps of the ViewModel class.
Dependencies are described as (accessor property name):(enumeration of referenced properties). "doubled": [ "counter" ], "is5times": [ "counter" ]
If you do not describe the dependencies, the html elements will not be updated.

Content of the html variable in main.js

<div>{{ counter }}</div>
<div>{{ doubled }}</div>
<!-- Disable the button after 5 presses -->
<button type="button" data-bind="onclick:countUp; disabled:over5times;">count up</button>

ViewModel class in main.js

class ViewModel {
  counter = 1;

  // Accessor property
  /**
   * Doubles the value of counter.
   * @type {number}
   */
  get doubled() {
    return this.counter * 2;
  }
  /**
   * Returns true if the value of counter is 5 or more.
   * @type {boolean}
   */
  get over5times() {
    return this.counter >= 5;
  }

  /**
   * Increment count
   */
  countUp() {
    this.counter++;
  }

  // dependencies
  $dependentProps = {
    // (accessor property name):(enumeration of referenced properties)
    "doubled": [ "counter" ],
    "is5times": [ "counter" ],
  };
}

See result.

See source.

Step 5. Output Filters

You can use output filters on the properties of ViewModel.
Write the pipe | and the filter name after the property in html.
You can specify options after the filter name, separated by a comma ,.
You can specify multiple filters using the pipe |.
Filters are provided as immutable methods of String, Number, and Array.

In terms of processing properties, it is similar to accessor properties, but differs in the following points.

Features of filters (differences from accessor properties)

There is no need to write dependencies. (You don't need to write $dependentProps.)
Only the output of a single property can be filtered. Filters cannot handle multiple properties.

List of Built-in Filter

Name	Options	Type
truthy	prop ? true : false
falsey	!prop ? true : false
not	!prop ? true : false
eq	[any]	prop == [any]
ne	[any]	prop != [any]
lt	[number]	prop < [number]
le	[number]	prop <= [number]
gt	[number]	prop > [number]
ge	[number]	prop >= [number]
embed	[format]	like printf, replace %s to prop
iftext	[string1][string2]	prop is true then [string1] else [string2]
isnull	prop == null
offset	[number]	prop + [number]
unit	[string]	prop + [string]
inc	[number]	prop + [number]
mul	[number]	prop * [number]
div	[number]	prop / [number]
mod	[number]	prop % [number]
at	...	string
charAt	...	string
charCodeAt	...	string
codePointAt	...	string
concat	...	string
endsWith	...	string
includes	...	string
indexOf	...	string
lastIndexOf	...	string
localCompare	...	string
match	...	string
normalize	...	string
padEnd	...	string
padStart	...	string
repeat	...	string
replace	...	string
replaceAll	...	string
search	...	string
s.slice	...	string
split	...	string
startsWith	...	string
substring	...	string
toLocaleLowerCase	...	string
toLocaleUpperCase	...	string
toLowerCase	...	string
toUpperCase	...	string
trim	...	string
trimEnd	...	string
trimStart	...	string
toExponential	...	number
toFixed	...	number
toLocaleString	...	number
toPrecision	...	number
at	...	Array
concat	...	Array
entries	...	Array
flat	...	Array
includes	...	Array
indexOf	...	Array
join	...	Array
keys	...	Array
lastIndexOf	...	Array
a.slice	...	Array
toLocaleString	...	Array
toReversed	...	Array
toSorted	...	Array
toSpliced	...	Array
values	...	Array
with	...	Array

Content of the html variable in main.js

<div>{{ message }}</div>
<div>{{ message|substring,4,15|toUpperCase }}<!-- QUICK BROWN --></div>

<div>{{ price }}</div>
<div>{{ price|toLocaleString }}<!-- 19,800 --></div>

ViewModel class in main.js

class ViewModel {
  message = "The quick brown fox jumps over the lazy dog";
  price = 19800;
}

See result.

See source.

Step 6. Conditional Branch Block

You can control the display using the properties of ViewModel as conditions.
Enclose the block to be controlled (a set of elements) with {{ if:(ViewModel property) }} ... {{ endif: }}. -> {{ if:val }} ... {{ endif: }}
Use {{ else: }} to display false conditions.
There is no else if.
A single property is used as a condition. -> Conditions cannot handle multiple properties.

Content of the html variable in main.js

<button type="button" data-bind="onclick:change">change!!!</button>
{{ if:val }}
  <div>val is true</div>
{{ else: }}
  <div>val is false</div>
{{ endif: }}

ViewModel class in main.js

class ViewModel {
  val = true;
  change() {
    this.val = !this.val;
  }
}

See result.

See source.

Step 7. Loop Block

You can repeat the display block using the array properties of ViewModel.
Enclose the block to be repeated (a set of elements) with {{ loop:(ViewModel property) }} ... {{ endloop: }} in html.
- {{ loop:animals }} ... {{ endloop: }}
- {{ loop:fruits }} ... {{ endloop: }}
Within the repeating block, describe the array elements using dot notation with wildcard *.
- animals.*
- fruits.*.name
- fruits.*.age

Content of the html variable in main.js

<ul>
{{ loop:animals }}
  <li>{{ animals.* }}</li>
{{ endloop: }}
</ul>
<ul>
{{ loop:fruits }}
  <li>{{ fruits.*.name }}({{ fruits.*.color }})</li>
{{ endloop: }}
</ul>

ViewModel class in main.js

class ViewModel {
  animals = [ "cat", "dog", "fox", "pig" ];
  fruits = [
    { name:"apple", color:"red" },
    { name:"banana", color:"yellow" },
    { name:"grape", color:"grape" },
    { name:"orange", color:"orange" },
    { name:"strawberry", color:"red" },
  ];
}

See result

See source.

Step 8. Initialization Event Handler

You can set the callback method $connectedCallback, which is an initialization event handler, in the ViewModel class.
The initialization event occurs when a component is created.
You can specify async for the callback method.
The callback method does not have any arguments.
In the sample, it fetches repository information from GitHub's API.

Content of the html variable in main.js

<ul>
  {{ loop:commits }}
  <li>
    {{ commits.*.sha|s.slice,0,7 }} - {{ commits.*.commit.message }} by {{ commits.*.commit.author.name }}
  </li>
  {{ endloop: }}
</ul>

ViewModel class in main.js

class ViewModel {
  commits = [];
  async $connectedCallback() {
    const response = await fetch("https://api.github.com/repos/mogera551/quel/commits?per_page=3&sha=main");
    this.commits = await response.json();
  }
}

See result

See source.

Step 9. Write Event Handler

You can set the callback method $writeCallback, which is a write event handler, in the ViewModel class.
The write event occurs when there is a write to the properties of ViewModel.
You can specify async for the callback method.
The arguments of the callback method are the written property name and the loop index array.
Normally, ViewModel properties associated with input DOMs are automatically updated, but this is used when you want to do some other processing after updating.
In the sample, it fetches repository information from GitHub's API.

Content of the html variable in main.js

display 
<select data-bind="value:display_count">
  <option value="3">3</option>
  <option value="4">4</option>
  <option value="5">5</option>
</select> items.
<ul>
  {{ loop:commits }}
  <li>
    {{ commits.*.sha|s.slice,0,7 }} - {{ commits.*.commit.message }} by {{ commits.*.commit.author.name }}
  </li>
  {{ endloop: }}
</ul>

ViewModel class in main.js

class ViewModel {
  display_count = "3";
  commits = [];
  async getCommits(per_page) {
    const response = await fetch(`https://api.github.com/repos/mogera551/quel/commits?per_page=${per_page}&sha=main`);
    return await response.json();
  }
  async $connectedCallback() {
    this.commits = await this.getCommits(this.display_count);
  }
  async $writeCallback(name, indexes) {
    if (name === "display_count") {
      // when changed display_count property
      this.commits = await this.getCommits(this.display_count);
    }
  }
}

See result

See source.

Step 10. Default Properties & Two-Way Binding

The properties of the html elements in the table below can be set as default properties, allowing you to omit the specification of the properties of the html elements when binding.
- data-bind="value:message"->data-bind="message"
- data-bind="textContent:message"->data-bind="message"

Tag	Type Attribute	Property
input	radio	checked
input	checkbox	checked
input	other than above	value
select	value
textarea	value
button	onclick
a	onclick
form	onsubmit
other than above	textContent

When binding the default properties of html input elements and the properties of the ViewModel class, if the properties of the input HTML elements are updated, the properties of the ViewModel class are also automatically updated (two-way binding).
The target input elements are input, select, textarea.
In the case of two-way binding, do not specify a filter for output. If necessary, specify the input filter number for type conversion. data-bind="num|number"
The method of specifying the input filter is the same as the normal filter.

Content of the html variable in main.js

<div data-bind="message"></div>
<div>
  <input type="text" data-bind="message">
</div>
<div>
  <textarea data-bind="message"></textarea>
</div>
<div>
  <button type="button" data-bind="clearMessage">clear message</button>
</div>
<div>
  <select data-bind="num|number">
    <option value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
    <option value="4">4</option>
    <option value="5">5</option>
    <option value="6">6</option>
    <option value="7">7</option>
    <option value="8">8</option>
    <option value="9">9</option>
    <option value="10">10</option>
  </select>
  {{ double }}
</div>

ViewModel class in main.js

class ViewModel {
  num = 1;
  message = "";
  get double() {
    return this.num + this.num;
  }
  clearMessage() {
    this.message = "";
  }
  $dependentProps = {
    "double": ["num"]
  }
}

See result

See source.

Step 11. Binding Styles

When binding the style attribute of an html element and a property of the ViewModel class, write it as style.(style attribute of the element):(property of ViewModel). For example, style.color:numberColor.

Content of the html variable in main.js

<input type="number" data-bind="num|number; style.color:numberColor">

ViewModel class in main.js

class ViewModel {
  num = 5;
  get numberColor() {
    return this.num > 10 ? "red" : "black";
  }
  $dependentProps = {
    "numberColor": ["num"]
  }
}

See result

See source.

Step 12. Binding Classes

When binding the class attribute of an html element and a property of the ViewModel class, write it as class.(class name):(property of ViewModel). For example, class.over:isOver.
If the property of the ViewModel class is true, the class name is added to the class attribute of the element.
If the property of the ViewModel class is false, the class name is removed from the class attribute of the element.

Content of the html variable in main.js

<style>
.over {
  color:red;
}
</style>
<input type="number" data-bind="num|number; class.over:isOver">

ViewModel class in main.js

class ViewModel {
  num = 5;
  get isOver() {
    return this.num > 10;
  }
  $dependentProps = {
    "isOver": ["num"]
  }
}

See result

See source.

Step 13. Using context variables and wildcards in repeat blocks

You can declare accessor properties using wildcards within repeat blocks. ex. members.*.no, members.*.isAdult
You can access properties using wildcards within accessor properties that use wildcards in repeat blocks. ex. The part where members.*.age is referenced within members.*.isAdult.
You can use context variables (index values) in accessor properties that use wildcards in repeat blocks.
- The context variable this.$1 is referenced within the property.
You can use index values in event handlers within repeat blocks.
- The index value is passed as the second argument to the event handler. ex. $1 in popup(e, $1)
You can directly use context variables (index values) within repeat blocks. ex. $1|offset,1

Content of the html variable in main.js

<style>
.adult {
  color:red;
}
</style>
{{ loop:members }}
<div data-bind="class.adult:members.*.isAdult">
  {{ members.*.no }} = {{ $1|offset,1 }}:{{ members.*.name }}, {{ members.*.age }}
  <button type="button" data-bind="onclick:popup">popup</button>
</div>
{{ endloop: }}

ViewModel class in main.js

class ViewModel {
  members = [
    { name:"佐藤　一郎", age:20 },
    { name:"鈴木　二郎", age:15 },
    { name:"高橋　三郎", age:22 },
    { name:"田中　四郎", age:18 },
    { name:"伊藤　五郎", age:17 },
  ];
  get "members.*.no"() {
    return this.$1 + 1;
  }
  get "members.*.isAdult"() {
    return this["members.*.age"] >= 18;
  }

  popup(e, $1) {
    alert(`選択したのは、${$1 + 1}行目です`);
  }

  $dependentProps = {
    "members.*.isAdult": [ "members.*.age" ]
  }
}

See result

See source.

Step 14. Manipulating array properties

When updating (adding, deleting, sorting) the array properties of ViewModel, create a new array with an immutable method and assign it. concat method of add()
When updating the elements of the array properties of ViewModel, you can update using a wildcard. <input type="text" data-bind="fruits.*">
The reflection to html is done automatically.

Content of the html variable in main.js

<button type="button" data-bind="onclick:add">add grape</button>
<button type="button" data-bind="onclick:dump">dump fruits</button>
{{ loop:fruits }}
<div><input type="text" data-bind="fruits.*">{{ fruits.* }}</div>
{{ endloop: }}

ViewModel class in main.js

class ViewModel {
  fruits = ["apple", "orange", "strawberry"];
  add() {
    // Add elements with an immutable concat and assign to the fruits property.
    // Do not use mutable `push`.
    this.fruits = this.fruits.concat("grape");
  }
  dump() {
    alert(JSON.stringify(this.fruits));
  }
}

See result

See source.

Step.15 ToDoリストを作ってみよう

仕様

チュートリアルのindex.htmlを使用する
入力部分
- 入力欄と追加ボタンを用意する
- 追加ボタンを押すと入力欄の内容をToDoリストに追加し、入力欄をクリア
- 入力欄に入力がない場合追加ボタンは非活性化disabled

リスト部分

<ul>でリスト表示する
リスト要素毎に、チェックボックス、ToDoの内容、削除ボタンを表示
チェックボックスをチェックすると、ToDoの内容を打消し線で装飾
打消し線はクラス属性(completed)で実現

削除ボタンを押すと当該行のToDoをリストから削除する

`html`のモック

<style>
.completed {
text-decoration: line-through;
}
</style>
<!-- 入力部分 -->
<div>
<form data-bind="add">
<input type="text">
<button>追加</button>
</form>
</div>
<!-- リスト部分 -->
<ul>
<li>
<input type="checkbox">
<span>ToDoの内容</span>
<button type="button">削除</button>
</li>
<li>
<input type="checkbox" checked>
<span class="completed">ToDoの内容</span>
<button type="button">削除</button>
</li>
</ul>

モックを見る

ToDo情報を格納するオブジェクトの型定義

ToDoの内容content

完了フラグcompleted

/**
* @typedef {Object} TodoItem
* @property {string} content
* @property {boolean} completed
*/

ViewModelクラスで保持する情報

入力欄のテキストcontent

ToDoリスト(TodoItemのリスト)todoItems

配列を保持する場合、初期値として空の配列を入れる

class ViewModel {
/** @type {string} input text */
content = "";
/** @type {TodoItem[]} todo list, set empty array as initial value */
todoItems = [];
}

htmlの入力部分

モックの入力部分を元にして作成
入力欄とViewModelクラスのcontentをバインド。data-bind="content"
submit時、ViewModelクラスのaddメソッドを呼び出す。呼び出し時、preventDefaultフィルタで、event.preventDefault()を実行する。data-bind="add|preventDefault"
入力欄に入力がない場合追加ボタンは非活性化。data-bind="disabled:content|falsey"
- 追加ボタンのdisabledプロパティとViewModelクラスのcontent|falseyをバインド
- content|falseyは、!contentと同じ意味
```
<div>
<form data-bind="add|preventDefault">
<input data-bind="content">
<button data-bind="disabled:content|falsey">追加</button>
</form>
</div>
```

ViewModelのaddメソッド

入力欄のテキストからToDoリストの要素を生成し、ToDoリストに追加し、ToDoリストを更新
- ミュータブルなpushではなくconcatを使う

追加後、入力欄のテキストをクリアthis.content = ""

class ViewModel {
/**
* add todo item
*/
add() {
const { content } = this;
this.todoItems = this.todoItems.concat({ content, completed:false });
this.content = "";
}
}

htmlのリスト部分

モックのリスト部分を元にして作成
ToDoリストの繰り返すブロックを{{ loop: }} ～ {{ endloop: }}で括る
チェックボックスのチェック状態とToDoの完了フラグをバインドする。data-bind="todoItems.*.completed"
ToDoの内容の表示{{ todoItems.*.content }}
ToDoの完了フラグの状態によりクラス属性にcompletedを追加、削除する。data-bind="class.completed:todoItems.*.completed"

削除ボタンを押すとViewModelクラスのdeleteメソッドを呼び出す。data-bind="delete"

<ul>
{{ loop:todoItems }}
<li>
<input type="checkbox" data-bind="todoItems.*.completed">
<span data-bind="class.completed:todoItems.*.completed">{{ todoItems.*.content }}</span>
<button type="button" data-bind="delete">削除</button>
</li>
{{ endloop: }}
</ul>

ViewModelのdeleteメソッド

deleteメソッドは、繰り返しブロック内にあるため、第2引数にインデックスが渡る
ToDoリストからインデックスの指す要素を削除し、ToDoリストに代入する。
- ミュータブルなspliceではなくtoSplicedを使う
```
class ViewModel {
/**
```
- delete todo item
- @param {Event} e
- @param {number} $1 loop context index */ delete(e, $1) { this.todoItems = this.todoItems.toSpliced($1, 1); } }

完成

main.js

const html = `
<style>
  .completed {
    text-decoration: line-through;
  }
</style>
<div>
  <form data-bind="add|preventDefault">
    <input data-bind="content">
    <button data-bind="disabled:content|falsey">追加</button>
  </form>
</div>
<ul>
  {{ loop:todoItems }}
  <li>
    <input type="checkbox" data-bind="todoItems.*.completed">
    <span data-bind="class.completed:todoItems.*.completed">{{ todoItems.*.content }}</span>
    <button type="button" data-bind="delete">削除</button>
  </li>
  {{ endloop: }}
</ul>
`;

/**
 * @typedef {Object} TodoItem
 * @property {string} content
 * @property {boolean} completed;
 */

class ViewModel {
  /** @type {string} input text */
  content = "";
  /** @type {TodoItem[]} todo list, initial value empty array */
  todoItems = [];
  /**
   * add todo item
   */
  add() {
    this.todoItems = this.todoItems.concat({content:this.content, completed:false}));
    this.content = "";
  }
  /**
   * delete todo item
   * @param {Event} e
   * @param {number} $1 loop index
   */
  delete(e, $1) {
    this.todoItems = this.todoItems.toSpliced($1, 1);
  }
}

実行結果を見る

memo

install @rollup/plugin-terser

npm install @rollup/plugin-terser --save-dev

bundle

npx rollup -c
npx rollup -c rollup-dev.config.js

tag

git tag v0.9.28 
git push origin --tags

mogera551 / quel

readme

What is Quel

Our goal

The main features

Getting Start

Install Test

The development flow

Write custom elements in HTML

Create corresponding single file component

Define the class to store and manipulate state

Define the HTML template.

Define the CSS.

Associate custom elements with component modules

Tutorial

First

Step 1. Embedding properties

Step 2. Property Binding

Step 3. Event Binding

Step 4. Accessor Properties

Step 5. Output Filters

List of Built-in Filter

Step 6. Conditional Branch Block

Step 7. Loop Block

Step 8. Initialization Event Handler

Step 9. Write Event Handler

Step 10. Default Properties & Two-Way Binding

Step 11. Binding Styles

Step 12. Binding Classes

Step 13. Using context variables and wildcards in repeat blocks

Step 14. Manipulating array properties

Step.15 ToDoリストを作ってみよう

仕様

htmlのモック

ToDo情報を格納するオブジェクトの型定義

ViewModelクラスで保持する情報

htmlの入力部分

ViewModelのaddメソッド

htmlのリスト部分

ViewModelのdeleteメソッド

完成

memo

`html`のモック